specification

GENERAL SPECIFICATION OF WORKS FOR

36 CREMORE LAWN, GLASNEVIN Date: 20.10.2009

Job no: 2008_07

48 Lower Mount St.

Dublin 2

Ireland [RegisteredAddress]

T: -

F: -

E: -

+353 1 5241227

+353 1 5241326

[email protected]

SPECIFICATION OF WORKS JOB NO. 2008_07

PROJECT : 36 Cremore Lawn, Glasnevin

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01 GENERAL REQUIREMENTS

1 GENERAL

Precedence

General: Where documents conflict, the following orders of precedence apply:

Information written into [or selected in) work schedules overrides contract drawings, which override the reference specification.

Existing services

Identification: Before starting work, check and mark positions of services. Where positions are not shown on drawings obtain relevant

details and permissions from service authorities, statutory undertakers or other owners.

Plant and materials Materials: Supply all necessary materials and products, including components, equipment and accessories.

Site equipment: Provide all necessary equipment including appliances, vehicles, consumables, tools, temporary works, scaffolding,

cabins and other site facilities.

2 DEFINITIONS

Actions

• Submit: Submit documentary information to the customer’s agent (the consultant) on request.

• Give notice: Inform customer’s agent (the consultant) in writing of outcome of action or instruction.

• Remove: Disconnect, dismantle as necessary and take out designated products or work and associated fastenings, supports

and bedding materials. Dispose of materials not identified for retention.

• Fix/ Fixing: Unload, handle, store, place and fasten in position including labours and use of site equipment.

• Set aside for reuse: Do not damage designated products or work. Clean off bedding and jointing materials. Stack neatly,

adequately protect and store until required.

• Make good: Execute local remedial work to designated area. Make secure, sound and neat.

• Replace: Supply and fix new products matching those removed. Execute work to match original state of that removed.

• Repair: Execute remedial work to designated products. Make secure, sound and neat.

• Refix: Fix removed products identified for reuse.

• Ease: Adjust moving parts of designated products or work to achieve free movement and good fit in open and closed

positions.

• As existing: Provide products and work of the same appearance and features as the original, excluding ageing and

weathering. Make joints between existing and new work as inconspicuous as possible.

3 GENERAL TECHNICAL REQUIREMENTS

Products and execution

General quality:

• Products generally: New. Proposals for recycled products will be considered.

• Supply of each product: From the same source or manufacturer.

• Whole quantity of each product required to complete the work: Consistent kind, size, quality and overall appearance.

• Product tolerances: Where critical, measure a sufficient quantity to determine compliance.

• Execution generally: Fix, apply, install or lay products securely, accurately, plumb, neatly and in alignment.

• Colour batching: Do not use different colour batches where they can be seen together.

• Dimensions: Check on-site dimensions.

• Finished work: Not defective, e.g. not damaged, disfigured, dirty, faulty, or out of tolerance.

• Ducts, chases and holes: Form during construction rather than cut. Where cutting/drilling is necessary submit proposals

before beginning operation.

Sizes:

• General dimensions: Nominal.

• Cross section dimensions of timber: Finished dimensions.

Substitution: Products: If an alternative product to that specified is proposed submit relevant documentation, including: -

• manufacturer and product reference;

• cost;

• availability;

• relevant standards; and

• copy of warranty/ guarantee.

Obtain approval before ordering the product.



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Work: If alternative work to that specified is proposed, obtain approval before execution.

Reasons: Submit reasons for the proposed substitution.

Manufacturers’ recommendations: • General: Comply with manufacturer’s current printed recommendations and instructions. Keep copies on site.

• Changes to recommendations or instructions since close of tender: Submit details.

• Ancillary products and accessories: Use those supplied or recommended by main product manufacturer.

• Agrement certified products: Comply with limitations, recommendations and requirements of relevant valid certificates.

Defects in existing work: • Reporting undocumented defects: When discovered, immediately give notice. Do not proceed with affected related work until

response has been received.

• Documented remedial work: Do not execute work which may:

- hinder access to defective products or work; or

- be rendered abortive by remedial work.

Accuracy, appearance and fit: Tolerances and dimensions: If likely to be critical to execution or difficult to achieve, as early as possible either:

• submit proposals; or

• Arrange for inspection of appearance of relevant aspects of partially finished work.

General tolerances (maximum): To BS 5606, tables 1 and 2.

4 TIMBER PROCUREMENT

Sourcing

Timber (including timber for wood based products): Obtain from well managed forests and/ or plantations.

Documentation:

When certification is required submit either:

• Documentary evidence (which has been or can be independently verified) regarding the provenance of all timber supplied; or

• Evidence that suppliers have adopted and are implementing a formal environmental purchasing policy for timber and wood

based products. •

5 NOTIFICATION, TESTING AND CERTIFICATION

Work to existing buildings

Submit commencement notice to Local Authority.

Sound insulation testing:

• Action: Construction to meet stipulated quality standard.

• Certification: Test results.

• Submit: To customer/ consultant and to Building Control.

Continuity of insulation

• Action: Demonstrate that an appropriate system of site inspection is in place.

• Certification: Reports signed by a suitably qualified person.


Notification of proposed plumbing work:

• Action: Notify Water Company.

• Submit: Approved plumber certificate to customer/ consultant.

Commissioning of heating and hot water systems:

• Action: Commission all fixed building services.

• Certification: Notice from suitably qualified person carrying out the work.


Commissioning of electrical systems:

• Action: Commission all electrical systems.

• Certification: Evidence of compliance of systems signed by approved competent person.




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02 DEMOLITION AND SITE CLEARANCE

Scope:

This section covers:

• Small scale demolition [e.g. forming openings in existing structures and removing existing small single storey extensions and ancillary buildings)

and stripping out.

• Site clearance.

1 EXECUTION

Demolition and stripping out Survey: Before starting work, carry out a survey and submit a report and method statement covering:

• condition and demolition of the structure;

• removal of hazardous materials; and

• protection of personnel and the public. Demolition: In accordance with BS 6187.

• Services that will be affected by the works: Locate and mark positions.

Site clearance Removing trees, shrubs and hedges:

In accordance with British HSE/ Arboriculture and Forestry Advisory Group Safety Guides.

• Felling: Cut down shrubs and smaller trees and grub up roots. Cut down larger trees and remove stumps and roots mechanically.

• Arisings: Remove from site. On-site chipping and shredding permitted.

• Clearing site: Clear site of rubbish, debris and general vegetation. Do not compact topsoil.

• Removing walls and pavings: Break up and remove from site.

• Stripping topsoil: Strip topsoil from areas where there will be regrading and/ or construction work.

• Depth: Full depth of existing topsoil.

• Around trees: Do not remove topsoil from below the spread of retained trees.

Materials arising Materials and fittings designated to remain the property of the customer: Protect until removed by customer or end of contract.

Other components and materials arising: Property of the contractor.



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03 CONCRETE FOUNDATIONS AND FLOORS

Scope: This section covers:

• Excavation and filling to foundation trenches and ground bearing slabs and rafts.

• In situ concrete to foundations, slabs and rafts.

• Insulation boards and separation membranes below rafts/ slabs.

• Bar and fabric reinforcement to concrete.

• Proprietary precast concrete flooring systems.

• Underpinning to existing foundations.

Related work:

• Bases to roads and external pavings - see section 16 'External paving and decking', • Excavation and filling to drainage trenches - see section 19 'Drainage below ground'.

1 PRODUCTS

Hardcore Fill: Clean granular material, free from harmful matter and excessive dust and clay, well graded, passing a 75 mm BS sieve, comprising

one of:

• crushed hard rock and/ or quarry waste;

• crushed concrete, brick and/ or tile, free from plaster; or

• Gravel and/ or hoggin.

Venting hardcore Fill: Clean granular material, well graded, passing a 75 mm BS sieve but retained on a 20 mm BS sieve, comprising one of:

• crushed hard rock;


• Gravel.

In situ concrete generally

Standards: To BS EN 206-1 and BS 8500-2.

Type: Designated concrete or Standardized prescribed concrete. Designated concrete:

• Aggregate size [maximum): 20 mm.

• Use of recycled aggregates: Permitted

• Admixtures containing calcium chloride: Not permitted

Reinforcement Ribbed bar: To BS 4449, Strength grade, 460 B. Fabric: To BS 4483.

Tying wire: 1.63 mm [16 s.w.g.) black annealed.

Thermal insulation Standards:

• Mineral wool (MW): To BS EN 13162.

• Expanded polystyrene [EPS]: To BS EN 13163.

• Extruded polystyrene foam [XPS]: To BS EN 13164.

• Rigid polyurethane foam [PUR): To BS EN 13165.

• Phenolic foam [PF): To BS EN 13166.

• Cellular glass [CG]: To BS EN 13167.

Perimeter slab insulation:

• Material: Flooring grade thermal insulation.

• Thickness: 25 mm.

Damp proof membrane (dpm) below floor Hardcore bed: Gas retardant dpm, Agrement certified i.e.:

• Dpm / radon barrier [dupont radon plus gas barrier or similar approved] laid in accordance with the recommendations of IS

325: part 2: 1995 code of practice for use of masonry, BS 8102: 1990 code of practice for protection of structures against

water from the ground, BS 8215: 1991 code of practice for design and installation of damp-proof courses in masonry

construction and clause 11 of BS cp 102: 1973 code of practice for protection of buildings from water from the ground and

with manufacturers instructions.

Radon Sump



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Radoncare radon sump or similar approved with gas venting system in accordance with BS 4660: 1989 (1998) specification for

unplasticised Polyvinyl Chloride (PVC-U) pipes and plastic fittings of nominal sizes 110mm and 160mm for below ground gravity

draining and sewerage. Venting externally to be installed within the hardcore layer to manufacturer's specifications

2 EXECUTION

General Site batching and mixing of concrete: To BS 8000-2.1. Placing and compacting concrete:

• Surfaces to receive concrete: Clean.

• Temperature range for concrete: 5-30°C. Do not place against frozen or frost covered surfaces.

• Compaction: Compact fully.

Fixing reinforcement: To BS 7973-1 and -2.

• Condition at time of placing concrete: Free from corrosive pitting, loose millscale, loose rust and contaminants.

• Cover (minimum): 40 mm.

• Laps (minimum):

- To bar reinforcement: 300 mm, securely tied.

- To fabric reinforcement: 250 mm, securely tied.

Surface deviation [maximum] of concrete floors:

• Concrete to receive direct sheet/ tile finishes: 5 mm under a 3 m straightedge and 2 mm under a 1 m straightedge.

• Concrete to receive screeds/ beds up to 50 mm thick: 10 mm under a 3 m straightedge.

Curing and protecting concrete:

• Evaporation: Limit throughout curing period. Cover immediately after compacting. Replace cover immediately after finishing

operations.

• Curing periods (minimum):

- Surfaces which in the finished building will be exposed to the elements and wearing surfaces of floors and

pavements: 10 days.

- Other structural concrete surfaces: 5 days.

Worked finishes to green concrete:

• Brushed: Light even texture.

• Wood floated: Slightly coarse texture with no ridges or steps.

• Smooth floated: Even texture, with no ridges or steps.

• Trowelled: Uniform, smooth but not polished surface, free from trowel marks and other blemishes, and suitable to receive thin

flooring materials.

Fill:

• Placing fill generally:

- Excavations and areas to be filled: Free from loose soil, rubbish and standing water.

- Freezing conditions: Do not use frozen materials or materials containing ice. Do not place fill on frozen surfaces.

- Filling against structures, membranes and buried services: Maintain stability.

• Backfilling around foundations:

- Under concrete and pavings: Hardcore.

- Under grassed areas and landscaped areas: Material excavated from the trench. Lay and compact in 300 mm

[maximum) layers.

Foundations • Trenches for strip foundations: With stable sides. Width at base equal to width of foundations.

• Mud, rock projections, boulders and hard spots: Remove. Replace with granular fill, well consolidated.

• Local soft spots: Harden by tamping in granular fill.

• Water: Keep excavations free from water.

• Trenches for trench fill foundations: With vertical sides. Width equal to width of foundations.

• Timing: Excavate immediately before laying concrete.

• Plain concrete foundations:

• Steps in concrete strip foundations:

• Height: Not more than foundation thickness.

• Overlap between strip foundations [minimum]: 300 mm, or twice step height, or twice foundation thickness, whichever is

greatest.

In situ concrete rafts and floor slabs

Excavation:

• Surplus materials: Remove from site.

• Mud, rock projections, boulders and hard spots: Remove. Replace with granular fill, well consolidated.

• Local soft spots: Harden by tamping in granular fill.



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Fill:

• Hardcore: Spread and level in 150 mm [maximum] layers.

• Thoroughly compact each layer.

• Venting hardcore: Spread and level in 150 mm [maximum) layers. Thoroughly compact each layer, whilst maintaining enough

voids to allow sufficient venting. Blinding to substrate:

• Hardcore: 25 mm [minimum) sand blinding.

• Venting hardcore: 50 mm [minimum) concrete blinding.

• Permissible deviation on surface level: +0 -25 mm. Underslab thermal insulation: Butt boards. • Polyethylene membrane below slab: Loose lay, tape joints.

Work to existing

Underpinning:

• Execution: Comply with recommendations of BS 8004.

• Type: Continuous. Carry out in discrete blocks, length 1000 mm (maximum).

• General:

- Block and working space: Excavate together.

- Formation preparation: Remove or compact loose material.

- Casting underpinning: In one lift. Leave a gap beneath existing foundation.

- Packing: After underpinning has cured, hard pack gap between underpinning and existing foundation. After packing

has cured, excavate for adjacent underpinning.

• Split sleeves: Sleeve around services passing through underpinning, to give 50 mm [minimum) clearance all round.



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04 MASONRY CONSTRUCTION Scope:


• Laying bricks, blocks and stone in courses on a mortar bed to form walls, partitions, chimneys, etc.

• Related items for building in, including flue blocks, air bricks, proprietary metal or concrete lintels and precast concrete components generally.

• Accessories including wall ties, flexible damp proof courses, cavity closers and leadwork built into masonry.

• Work to existing masonry walling.

Related work:

• Brickwork in manholes and inspection chambers - see section 19 'Drainage below ground'.

1 PRODUCTS

Bricks

• Clay bricks: To BS 3921 or to BS EN 771-1.

• Calcium silicate bricks: To BS 187 or to BS EN 771-2.

• Concrete bricks: To BS 6073-2 or to BS EN 771-3.

Blocks

• Aggregate concrete blocks: To BS 6073-2 or to BS EN 771-3.

• Autoclaved aerated concrete [AAC] blocks: To BS 6073-2 or to BS EN 771-4.

• Manufactured stone blocks: To BS 6457 or to BS EN 771-5.

Cement gauged mortar

Cement:

• Portland cement: To BS EN 197-1. - Type: CEM I.

• Sulfate resisting cement: To BS 4027, Kitemarked.

- Strength class: 42.5.

- Masonry cement: To BS EN 413-1.

- Sand for site-made mortar: To BS EN 13139.

- Grading: 0/2 [FP or MP] with category 3 fines content. Ready mixed lime/ sand: To BS EN 998-2.

• Lime: Nonhydraulic to BS EN 459-1.

- Type: CL 90-5.

In situ concrete fill

Concrete: To BS EN 206-1 and BS 8500-2.

• Type: Designated concrete GEN 1 or Standardized prescribed concrete ST2.

Wall ties • Standard: To DO 140-2 orto BS EN 845-1.

- Material: Austenitic stainless steel.

Opes and cavity trays Chemical dpc: Agrement certified.

Flexible dpcs:

• Polyethylene: To BS 6515.

• Bitumen polymer: Agrement certified.

• Pitch polymer: Agrement certified.

Cavity damp proof trays:

• Preformed cavity trays: Agrement certified.

• Site formed cavity trays: From Agrement certified dpc material.

• Remedial cavity tray systems: Agrement certified.



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Cavity insulation Factory made full fill or partial fill insulation system: Agrement certified.

• Material standards: As section 03 'Concrete foundations and floors', clause 'Thermal insulation'. Blown or injected cavity fill: Urea-formaldehyde foam to BS 5617 or Agrement certified product.

Cavity closers

Insulated cavity closers: Agrement certified.

Lintels

Standard: To BS EN 845-2. Fireplaces and chimney components Clay/ ceramic flue lining systems: To BS EN 1457. Concrete gas flue block systems: To BS EN 1858.

Fireplace components: To BS 1251. Fasteners to timber frame wall ties Annular ring shanked nails:

• Material: Stainless steel. • Length [minimum): 50 mm. • Shank [minimum]: 3 mm.

2 EXECUTION General

General

Basic brickwork and blockwork:

• Mortar joints: Lay units on full bed. Fill vertical joints.

• Lift height [maximum]: 1.2 m above other parts of work but not more than 1.5 m daily.

Basic rubble stonework:

• Mortar joints: Lay units on full bed. Fill voids and vertical joints. Avoid long continuous vertical joints.

Facework:

• Lowest courses: At least 150 mm below finished ground.

• Coursing: Plumb with consistent appearance.

• Junctions and joints with built-in elements and components: Align with walling joints.

Cleanliness: Keep units clean.

Horizontal dpcs (flexible]: Lay on full mortar bed. Lap 100 mm [minimum] at joints and fully lap at angles.

• Width: At least full width of masonry leaf. Do not cover edges of dpc with mortar or project into cavity.

• Overlying construction: Full even bed of mortar to receive next masonry course.

• Overall finished joint thickness: As close to thickness of general walling joints as practicable. Ground level dpcs:

• Level: At least 150 mm above finished ground.

• Joint with damp proof membrane: Continuous and sealed.

Sill dpcs: In one piece. Turn up at back where the sill is in contact with inner leaf. Vertical dpcs (flexible): Dpcs to jambs of openings: Fully lap behind cavity tray at head and over horizontal dpc at sill. Project at least 25 mm into cavity and maintain full contact with frames. Cavity trays, site formed: As horizontal flexible dpcs. Chimney dpc at roof:

• Lead: 1.75-2 mm [code 4l.

• General: In accordance with Lead Sheet Association (LSA] 'Rolled lead sheet. The complete manual'.

• Surfaces to be embedded: Coat with high build bitumen based paint.

External cavity walls

Concrete cavity fill: In situ concrete.

• Level: Top of fill 75 mm (maximum) below ground.

Cleanliness: Keep cavity faces, ties and dpcs free from mortar and debris.

Cavity insulation:

• Joints between boards or batts: Clean with no gaps.

• Partial fill:

- Placement: Secure against face of inner leaf.

- Residual cavity: 50 mm (minimum), clear and unobstructed.

Perpend joint weep holes through outer leaf:

• Locations: Form immediately above base of cavity, at cavity trays and stepped dpcs.



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• Provision: At 1 metre (maximum) centres and at least two over each opening.

Ventilation ducts in external walling: Set across cavity, sloping away from inner leaf. Fill mortar joints to seal cavity.

Wall ties in masonry cavity walls:

• Placement: Embed 50 mm (minimum) in mortar beds and slope slightly downwards towards outer leaf. Set with drip within

residual cavity and pointing downwards.

• Spacing [fully filled and unfilled cavities): Stagger in alternate courses. Horizontal centres, 750 mm [maximum); vertical

centres, 450 mm (maximum).

• Spacing (partially filled cavities): Space evenly in nonstaggered rows. Horizontal centres, 600 mm (maximum); vertical

centres, 450 mm (maximum).

• Ties supporting partial fill insulation: Fit with insulation retaining clips.

• Additional ties: At 300 mm (maximum) vertical centres within 225 mm of reveals of unbonded openings/ edges.

Cladding to frames and backing walls

Wall ties to masonry clad timber frame walls:

• Fixing: Fix securely to studs with annular ringed shank nails.

• Placement: Embed 50 mm (minimum] in mortar beds and slope slightly downwards from timber frame.

• Spacing: Horizontal centres, as studs. Vertical centres, 450 mm (maximum) for stud centres up to 450 mm, 375 mm

(maximum) for stud centres up to 600 mm.

• Additional ties: At 300 mm (maximum] vertical centres within 225 mm of reveals of unbonded openings/ edges.

Workmanship to alterations/ extensions generally Coursing: Line up with existing work.

• Bonding of new walls to existing: Pocket joints.

• Depth (minimum): 100 mm.

Vertical spacing for brickwork: 4 courses high at 8 course centres.

• Vertical spacing for blockwork: Every other course.

• New and existing facework in the same plane: Bond at every course to achieve continuity of bond and coursing.

Forming openings in existing walling:

• External reveals: Finish with staggered half and whole masonry units.

• Head: Cut out 300 mm [minimum) each side of finished opening width for dpc or cavity tray and for bedding lintels.

• Vertical dpcs to opening:

- Cavity walling: Insulated cavity closer, type to match cavity width.

- Solid walling: Make good internal reveals onto vertical insulated flexible dpc 100 mm (minimum) wide.

• Sill or threshold: Cut out 300 mm (minimum) each side of finished opening width for dpc and for bedding sill or threshold.

On completion make good to masonry.

• Additional ties: At 300 mm [maximum) vertical centres within 225 mm of reveals of unbonded openings/ edges.

Support of existing work: Consolidate joint above inserted lintel or masonry with semidry mortar.

Chemical dpc system:

• Installation: To BS 6576 by a firm approved by the manufacturer.

• Making good to exposed injection holes: Fully fill with mortar to match existing masonry in colour and texture. Finish

neatly and flush.

• Guarantee: Insured protection administered by an independent insurance protection company. Guarantee period from

completion of installation, 20 years (minimuml. Submit certificates/ guarantees at completion of installation.

Cavity insulation, blown or injected:

• Suitability of walling: Check to BS 8208-1 before and during filling of cavities. Defects: Report immediately.

• Urea formaldehyde foam installation: To BS 5618. Installer to hold current BSI Certificate of Registration of Assessed

Capability.

• Other cavity fill materials: Installer approved in accordance with the BBA Surveillance Scheme.

• Gaps and openings: Seal with tightly packed mineral wool to prevent loss of fill.

Cavity ventilating air bricks/ grilles: Remove. Seal openings into cavity.

• Making good: Remove temporary blocks from vents and refix or replace air bricks. Fill injection holes, replacing existing

materials where possible. Obtain approval for appearance of first holes before completing remainder.

Repointing:

• Preparation: Cut out joints to 15-20 mm depth. Clean and dampen joints sufficiently to control suction.

• Cracked units in existing facework: Cut out and replace with matching masonry before repointing.

• Joint profile: Match existing.



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05 STEELWORK

Scope:

This section covers simple steel beams, joists and posts fabricated from hot rolled steel. Hot rolled steel frames and proprietary

lightweight steel framing systems are not included.

Related work:

• Rigid sheet fire protection - see section 12 'Plasterboard linings, plastering, rendering and screeding·.

1 PRODUCTS

Hot rolled steel Simple steel sections: To BS 4-1, BS EN 10055, BS EN 10056 and BS EN 10210, as appropriate.

• Steel designation: To BS EN 10025-2, grade S275.

- Sub-grade for external use: JR.

- Sub-grade for internal use: JO.

• Surface condition: Free from heavy pitting and rust, burrs, sharp edges and flame cutting dross.

Shop primer Primer: Zinc phosphate modified alkyd.

2 EXECUTION

Fabrication Cuts and holes: Accurate and neat.

Welding: Metal arc method to BS EN 1011-2.

• Welded joints: Fully fused, with mechanical properties at least those of the parent metal.

• Site welding: Submit proposals.

Galvanizing Standard: To BS EN ISO 1461.

• Preparation: Chemical cleaning.

• Mean coating thickness [minimum]: 85 J-lm.

Shop priming Preparation: Remove loose scale, loose rust, burrs, fins, sharp edges and weld spatter. Clean out crevices. Thoroughly degrease

surfaces, rinse using clean water and allow to dry. Priming: One full coat within 8 hours of preparation.

Installation Accuracy: Position members true to line. If necessary, level with steel packs of sufficient area to allow full transfer of loads to bearing

surfaces.

Washers: Place under bolt heads and nuts.

• Tapered washers: For bolt heads and nuts bearing on sloping surfaces. Match taper to slope angle and align correctly.



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06 STRUCTURAL TIMBER AND GENERAL CARPENTRY

1 PRODUCTS Graded softwood for structural members Strength class: To BS EN 338.

Joists: Regularized.

Trimmers and trimming joists/ rafters: 25 mm (minimum) wider than general members. • Strength class: As general joists/ rafters. Studs to loadbearing partitions: Regularized.

Studs to timber frame walls [site fabricated): Regularized.

Ungraded softwood for non-structural members Quality of timber: Free from decay, insect attack [except pinhole borers) and with no knots wider than half the width of the section.

Wall plates: Preservative treated.

Studs to non-loadbearing partitions: Regularized.

Plywood sheathing Standard: To BS 5268-2, classified for exterior use.

Vertical restraint straps Material: Stainless steel or galvanized low carbon steel.

• Section size [minimum): 30 x 2.5 mm.

• Form:

- Rafter restraint: Vertical twist type.

- Wallplate restraint: Cranked 100 mm one end.

- Length [minimum): 1 m.

Lateral restraint straps Material: Stainless steel or galvanized low carbon steel.

• Section size [minimum): 30 x 5 mm.

• Form: 150 mm cranked one end.

• Length [minimum):

- Along line of joists at intermediate floor: 1.2 m.

- Across joists at intermediate floor: Across 3 joists.

- Across rafters at gable: Across 3 rafters.

Framing anchors and truss clips Material: Stainless steel or galvanized low carbon steel.

Fasteners Material: Stainless steel or galvanized or sherardized low carbon steel.

Nails to timber substrate: To BS 1202-1 or to BS EN 10230-1.

• Length [into supporting structure): 40 mm (minimum), or full depth if less than 40 mm.

- Shank diameter [minimum): 3 mm.

Screws:

• Length [into supporting structure):

- To timber supports: 40 mm [minimum), or full depth if less than 40 mm.

- To supporting masonry [minimum): 63 mm.

• Shank diameter:

- Masonry screws [minimum): 4.8 mm.

- Wood screws [minimum): 8 gauge.

Plugs for masonry fixings using wood screws: Size to match screws.

Timber preservation Preservative treatment:

• Timber for general construction: To British Wood Preserving and Damp-proofing Association [BWPDA) Commodity

Specification C8.

• Timber frame external walls: To BWPDA Commodity Specification C9.

Preservative solution for site application to cut timbers: As recommended for the purpose by main treatment solution manufacturer.



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2 EXECUTION

General Structural use of timber: In accordance with BS 5268-2.

Processing preservative treated timber:

• Cutting and machining: Maximize before treatment.

• Extensively processed timber: Repeat treatment.

• Surfaces exposed by minor cutting and drilling: Apply two flood coats [minimum] of recommended treatment solution.

• Moisture content of wood and wood based products at time of installation [maximum]:

- Covered in generally unheated spaces: 24%.

- Covered in generally heated spaces: 20%.

- Internal in continuously heated spaces: 20%.

Additional studs, noggings and/or battens: Provide to support edges of sheet materials, and to wall/floor/ceiling mounted appliances,

fixtures, etc.

• Timber: Of adequate size and preservative treated as adjacent timbers.

Wall plates:

• Joints: Nailed half lap joints. Minimize number of joints,

• Do not use short lengths of timber.

• Bedding: Fully in fresh mortar. Lateral restraint straps:

• Spacing [maximum): 2 m centres.

• Cranked end: Place downwards in tight contact with cavity face of wall inner leaf.

• Fixing to joists/ rafters: At least four countersunk screws per strap, evenly spaced.

• Notching to timber members: Notch joists so that straps fit flush with surface. Do not notch rafters/ ties.

Vertical restraint straps:

• Spacing [maximum]: 2 m centres at eaves.

• Fixings to wallplate or rafters: At least two square twist nails.

• Fixings to masonry: At least four screws evenly spaced, with at least one screw located within 150 mm of the bottom end of

each strap.

Floor, ceiling and flat roof structure

Standard: To BS 8103-3.

Bowed joists: Install with positive camber.

Joists on hangers:

• Hangers: Bed directly on, and hard against, supporting construction. Do not use packs or bed on mortar.

• Joists: Cut to leave 6 mm [maximum) gap at each end. Rebate to lie flush with underside of hangers.

• Fixing to hangers: A nail in every hole.

• Herringbone strutting between joists: Make from 38 x 38 mm (minimum) softwood, or proprietary metal strutting.

• Spacing:

- Joist spans of 2.5-4.5 m: One row at centre span.

- Joist spans over 4.5 m: Two rows equally spaced.

• Outer joists against masonry walls: Position about 50 mm from masonry.

• Packing at restraint strap positions: Insert softwood folding wedges between joist and masonry and fix solid blocking between

joists along full length of each strap.

• Solid blocking size: Three quarters of joist depth [minimum) x 38mm.

• Packing at internal walls: Insert softwood folding wedges between joist and masonry on line of strutting and at 2 m [maximum)

centres.

Pitched roof structure Common rafter roof:

• Bowed rafters: Install with positive camber.

• Outer rafters against masonry gable walls: Position about 50 mm from masonry.

- Packing at restraint strap positions: As for joist packing description above.

• Fixing to timber supports: Use framing anchors or skew nail.

Trussed rafter roof:

• Handling and storage: Keep trussed rafters vertical.

• Erection: To BS 5268-3 and Trussed Rafter Association site installation guide.

• Fixing: Truss clips to bottom chords of standard trusses and to rafters of raised tie trusses bearing fully on wall plates.

• Bottom chords of standard trusses: Do not fix to internal walls until roofing is complete and cisterns [if required) are installed



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and filled.

• Bracing: Fix to every rafter, strut or tie with at least two round wire nails.

Wall framing and partition structure

Timber stud partitions:

Fixing: Use framing anchors or skew nail. Timber frame walling (site fabricated):

Fixing: Framing anchors.

Work to existing timber structure Replacement timber size generally: As material being replaced. Forming openings in existing sawn softwood floor/ roof:

• Extent: Minimize removal of existing structure.

• Fixing: Framing anchors.

Repairing and/ or replacing defective rafter ends:

• Sawn softwood rafters:

- Defective timber: Cut out full length of rafter from wallplate to first purlin [or other support).

• Riven hardwood or softwood rafters:

- Defective timber: Agree extent of removal before cutting existing.

Jointing: Traditional in-line timber to timber joint. Agree style before cutting out.

Repairing and/ or replacing defective purlin ends:

• Defective timber: Agree extent of removal before cutting out.

- Jointing: Steel plate reinforced or resin repair.

Repairing and/ or replacing defective joist ends:

• Defective timber: Agree extent of removal before cutting out.

- Jointing: Steel plate reinforced or resin repair or lap joint with bolted timber connectors.



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07 BOARD CLADDING AND SOFFITS •

Scope:


• External wall cladding, fascias and soffits of wood or plastics board or other rigid sheet material.

Related work:

• Plywood sheathing to timber frame walling - see section 06 'Structural timber and general carpentry',

• Render finishes on metal lathing - see section 12 'Plasterboard linings, plastering, rendering and screeding',

1 PRODUCTS

Wood weatherboarding

Wood:

• Quality (exposed surfaces): To BS 1186-3,

• Moisture content at time of fixing: 13-19%.

Plastics weatherboarding System: Agrement certified.

Rigid sheet cladding Plywood: To BS 5268-2, classified for external use.

Cement-bonded particleboard: To BS EN 634-2, external use.

Softwood battens and counterbattens General: Regularized softwood, free from decay and insect attack (except ambrosia beetle damage], preservative treated.

Timber preservation Preservative treatment: To British Wood Preserving and Dampproofing Association (BWPDA) Commodity Specification C8.


Breather membrane Standard: To BS 4016 or Agrement certified.

Fasteners Nails to timber substrate:

• Steel nails: To BS 1202-1 orto BS EN 10230-1.

- Material: Stainless steel or galvanized or sherardized low carbon steel.

• Copper nails: To BS 1202-2.

• Aluminium nails: To BS 1202-3.

• Length (into supporting structure): 40 mm (minimum], or full depth if less than 40 mm.

- Shank diameter (minimum): 3 mm.

- Screws: To BS 1210.

• Material: Brass or sherardized low carbon steel.

• Length (into supporting structure!:

- To timber supports: 40 mm [minimum], or full depth if less than 40 mm.

- To supporting masonry (minimum): 63 mm.

• Shank diameter:

- Masonry screws (minimum]: 4.8 mm.

- Wood screws (minimum): 8 gauge.

• Plugs for masonry fixings using wood screws: Size to match screws.

• Staples: Stainless steel.

•



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2 EXECUTION

Board cladding Breather membrane:

• Installation: Provide a complete barrier to water, snow and wind blown dust. Extend membrane below bottom edge of cladding

and into reveals of openings.

• Laps: Horizontal, 100 mm; vertical, 150 mm and staggered.

• Fasteners: Large head nails or staples.

Battens and counterbattens:

• Length [minimum): 1.2 m.

• Installation: Finish fastener heads flush with or slightly below batten face.

• Orientation:

- Support for horizontal boarding: Vertical battens.

- Support for vertical boarding: Horizontal battens on vertical counterbattens.

- Support for rigid sheet: Vertical battens.

• Setting out: In straight lines. Set vertical battens/ counterbattens over studs where available.

- Joints: Staggered on supports.

• Fasteners:

- Fasteners to masonry: Plugs and screws.

- Fasteners to timber: Annular ringed shank nails.

- Penetration: Finish fastener heads flush with or slightly below board surface.

- Fasteners to exposed surfaces: Space evenly in straight lines, in pairs across joints and sufficient distance from

edge of sheet to prevent damage.

Wood weatherboarding:

• General: Fix securely to give flat, true surfaces free from undulations, lipping, splits, hammer marks and protruding fasteners.

• Movement: Allow for movement of boards and fixings.

• Heading joints: Position centrally over supports and at least two board widths apart on anyone support.

• Lost head and small head nails: Punch below surfaces that will be seen in the completed work.

• Finishing system: Before fixing boards, apply appropriate primer/ base coat sealant to all surfaces. Apply liberally to end

grain.

Plastics weatherboarding:

• Temperature: Do not fix weatherboarding when ambient temperature is at or below 0 Degrees Celsius.

• Setting out: Allow for thermal movement of boards and fixings.

• Heading joints: Position centrally over supports and at least two board widths apart on anyone support.

• Rigid sheet cladding:

• General: Fix securely to give flat, true surfaces free from undulations, lipping, splits, hammer marks and protruding fasteners.

Preservative treated wood:

Surfaces exposed by minor cutting and/ or drilling: Apply two flood coats [minimum) of recommended treatment solution.

• Moisture content at time of fixing [maximum): 22%.

Work to existing

Removing existing cladding:

• General: Carefully remove cladding units, battens, underlay, etc. with minimum disturbance to retained cladding.

• Removed cladding units: Set undamaged units aside for reuse.



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08 TILE AND SLATE CLADDINGS AND ROOF COVERINGS

1 PRODUCTS

Tiles Plain or single lap tiles:

• Clay: To BS EN 1304.

• Concrete: To BS EN 490.

Slates • Natural slates: To BS EN 12326-1.

• Fibre cement slates: To BS EN 492, type NT.

Softwood battens and counterbattens General: Regularized softwood to BS 5534, preservative treated.

Timber preservation Preservative treatment: To British Wood Preserving and Dampproofing Association (BWPDA) Commodity Specification C8.


Breather membrane to cladding

Standard: To BS 4016 or Agrement certified.

Roofing underlay Reinforced bitumen membrane: To BS 747, type 1 F.

Breathable membrane: Agrement certified.

Eaves/ cladding bottom edge starter strip: To BS 747, type 5U.

Insulation Material standards: As section 03 ‘Concrete foundations and floors’, clause ‘Thermal insulation’.

Eaves ventilator trays Trays: Agrement certified.

• Free ventilation area (minimum): 25,000 mm2/m.

Hip irons Standard: To BS 5534.

• Material: Galvanized low carbon steel.

Fasteners Nails for slate or tile fixing:

• Stainless steel nails: Dimensions as BS EN 10230-1.

• Copper nails: To BS 1202-2.

• Aluminium nails: To BS 1202-3.

Nails for batten or underlay fixing: To BS 1202-1 or to BS EN 10230-1.

• Material: Galvanized or sherardized low carbon steel. Screws: To BS 1210.


Clips for tile fixing: As tile manufacturer’s recommendations.

Rivets for fibre cement slate fixing: As slate manufacturer’s recommendations.

Staples: Stainless steel.

Fastener size for slates/ tiles and to battens/ counterbattens:

• Nails:

- Length (into supporting structure): 40 mm (minimum], or full depth if less than 40 mm.

- Shank [minimum): 3.5 mm.

• Wood screws:

- Length (into timber supports): 40 mm (minimum], or full depth if less than 40 mm.

- Shank diameter (minimum): 8 gauge.


• Masonry screws:

- Length (into supporting masonry): 63 mm (minimum).

- Shank diameter (minimum) 4.8 mm.

Lead flashings and valley gutters

Rolled lead sheet: To BS EN 12588.



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2 EXECUTION

General Programme: Make roofing and/ or cladding sound and weathertight at earliest opportunity.

Pitched roof insulation:

• Insulation fitted between rafters: Butt joints, no gaps. Use fasteners where necessary to prevent slumping.

• Insulation fitted over rafters as sarking: Fit neatly with no gaps.

- Fixing: Secure with counterbattens.

Pitched roof underlay and/ or cladding breather membrane:

• Laying: Maintain consistent tautness.

• Vertical laps: 100 mm (minimum], coinciding with supports.

• Fasteners: Extra large head clout nails.

• Penetrations: Use purpose made seals or cut neatly.

Battens and counterbattens:

• Length (minimum): 1.2 m.

Setting out: In straight lines. Set out counterbattens over rafters or (for cladding) studs where available.

• Joints: Staggered on supports.

• Surfaces exposed by cutting: Apply two flood coats [minimum) of recommended treatment solution.

• Fasteners:

- Fasteners to masonry: Plugs and screws.

- Fasteners to timber: Annular ring shanked nails.

- Penetration: Finish fastener heads flush with or slightly below surface.

Setting out slates and/ or tiles:

General: Set out to true lines and regular appearance. Lay units with 5 mm (maximum) gapped butt joints. Align tails.

Ends of courses: Use extra wide units to maintain bond. Do not use units less than 150 mm wide.

• Top and bottom courses to slating or plain tiling: Non- standard length units to maintain gauge.

Leadwork: In accordance with the Lead Sheet Association [LSA) publication ‘Rolled lead sheet. The complete manual’.

• Flashings generally:

- Thickness: Code 4 (1.75 - 2 mml.

- Lengths (maximum): 1.5 m.

- End to end joint laps [minimum): 100 mm.

• Soakers: Code 3 (1.25 - 1.50 mm).

• Apron flashings, cover to roofing (minimum):

- Roof pitches from 20-30°: 220 mm.

- Roof pitches above 30°: 150 mm.

• Fixing into masonry bed joints: Secure with lead wedges.

Point up with mortar to match walling.

• Valley gutters:

- Thickness: Code 4 [1.75 - 2 mm).

- Lengths [maximum]: 1.5 m.

- End to end joint laps (minimum): 100 mm.

- Width: Layover and beyond tilting fillets.

- Fixing: Copper clout nails to underlap.

Tile and / or slate pitched roof coverings

Eaves ventilation trays: Fit to full width between rafters.

Underlay:

• Support at eaves: Softwood tilting fillet, preservative treated, or 9 mm external quality plywood fixed on tilt to drain to gutter, or

purpose made underlay carrier. Dress underlay or underlay support tray to form drip into gutter.

• Installation at bedded verges:

- Verge with bedded undercloak at gable wall: Carry underlay 50 mm onto outer leaf of wall and bed on mortar.

- Verge with nailed undercloak over bargeboard: Carry underlay over full width of verge.

• Installation at hips: Lay underlay courses over hip. Overlap 150 mm (minimum).

• Installation at unventilated ridge: Lay underlay courses over ridge. Overlap 100 mm [minimum).

• Installation at ventilated ridge: Lay underlay courses to provide an air gap at apex.

• Installation at metal valley gutter: Cut underlay over tilting fillets to lap onto metal valley. Do not lay under metal.

General fixing of tiles and/ or slates: As manufacturer’s fixing specification.

Eaves: Fix first course units (and undercourse units to slating and plain tiling) with tails projecting 50 mm over gutter or to centre of



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gutter.

Verges:

• Bedded verge with bedded undercloak:

- Undercloak to plain tile or slate roof covering: To match roofing units.

- Undercloak to single lap tile roof covering: Fibre cement sheet on mortar bed. Slope towards verge to project 38-50

mm beyond face of wall.

- Battens: Carry onto undercloak and finish 100 mm from verge edge.

- Verge units: Bed flush with undercloak on 75 mm wide mortar bed.

• Bedded verge with nailed undercloak:

- Undercloak to natural slate roof covering: To match roofing units.

- Undercloak to plain or single lap tile or to fibre cement slate roofing: Fibre cement sheet, nail fixed. Slope towards verge to project 38-50 mm beyond face of bargeboard.

- Battens: Carry onto undercloak and finish 100 mm from verge edge.

- Verge units: Bed flush with undercloak on 75 mm wide mortar bed.

Hips:

• Dry-fix hips: As manufacturer’s fixing specification.

• Mortar bedded hips:

- Roofing units: Cut and fix closely at hip.

- Hip irons: Screw to hip rafter or hip batten.

- Hip tiles: Bed in mortar, continuous to edges and solid to joints.

- Bottom hip tiles: Shape neatly to align with corner of eaves and fill ends with mortar finished flush.

Ridges:

• Ventilated (dry-fix) ridges: As manufacturer’s fixing specification.

• Unventilated [mortar bedded) ridges:

- Ridge tiles: Bed in mortar, continuous to edges and solid to joints.

- Ridge tiles at masonry supports or abutments: Where masonry walls support or abut ridge, secure ridge tiles within

900 mm of such walls with nails/ wire ties or screws.

• Gable end tiles: Fill ends with mortar finished flush.

Valley gutters: Cut roofing units to fit neatly. Valley width between units: 150 mm.

Work to existing Removing tiles/ slates to form opening:

• General: Remove roof covering/ cladding units, battens, underlay, etc. with minimum disturbance of retained coverings/

cladding.

- Removed units: Set aside for reuse.

Removing tiles/ slates for re-roofing/ re-cladding:

• General: Carefully remove tiles/ slates.

• Removed units: Set aside for reuse.

• Reusing existing tiles/ slates:

- General: Clean.

- Natural slate: Dress to remove defective material and redrill if necessary.

- Defective material: Remove from site.

- Quantity: Make up required unit quantities.



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09 FLAT ROOF COVERINGS

1 PRODUCTS

Decking Plywood: To BS 5268-2, external use.

Cement-bonded particleboard: To BS EN 634-2, external use.

• Joint cover strips: Reinforced bitumen membrane, type 5U.

Flat roof coverings Vapour control layer:

• Reinforced bitumen membrane: To BS 747.

• Proprietary system: Agrement certified.

• Bitumen membrane covering:

- Reinforced bitumen membrane: To BS 747.

- Modified bitumen membrane system: Agrement certified.

• Single layer polymeric membrane: Agrement certified.

Insulation Material standards: As section 03 'Concrete foundations and floors', clause 'Thermal insulation'.

Timber trims and fillets Timber trims: Softwood, preservative treated after machining, free from wane, pitch pockets, decay and insect attack.

Fasteners to decking Nails: To BS 1202-1 or to BS EN 10230-1.

• Material: Stainless steel or galvanized or sherardized low carbon steel.

• Length: Select length to drive into full depth of supporting timber or 40 mm [minimum) into substrate.

• Shank [minimum): 3.5 mm.

Lead flashings

Rolled lead sheet: To BS EN 12588.

Wood preservation

Preservative treatment: As section 7, ‘Board cladding and soffits’.

2 EXECUTION

Flat roof coverings

General:

• Substrates: Secure, clean, dry, smooth, free from frost, contaminants, voids and protrusions.

• Adverse weather: Do not lay coverings in high winds, wet or damp conditions or in extremes of temperature unless effective

temporary cover is provided over working area. Keep unfinished areas dry.

• Coverings: Attach firmly and fully seal.

Decking:

• Setting out: Fully support long edges at right angles to structure. Support end edges. Stagger end joints.

• Fixing: Fasteners at 150 mm [maximum] centres to edges and at 200 mm (maximum) centres at supports.

• Joint cover strips: 150 mm (minimum) wide. Lay centrally over joints. Adhere with bonding compound along edges.

Vapour control layer:

• Attachment: Bond to substrate.

• Laps [minimum): 75 mm. Fully seal with bitumen or proprietary product as per chosen system above.

Penetrations: Fully seal.

Laying insulation boards:

• Jointing: Butt together.

• Exposed edges: Enclose with vapour control layer to provide a continuous seal when overlapped by roof covering.

Bedding: Fully bond to vapour control layer.

Laying bitumen membrane:

• Venting first layer: Loose lay to deck only. Do not carry up angle fillets or vertical surfaces.

- Long edges: Overlap 50 mm.

- Ends: Butt together.

• Bonded layers:

- Pour and roll bonding: Hot compound. Remove excess compound at laps of capsheet.

- Torch-on bonding: Leave a continuous bead of compound at laps of capsheet.

• Laps: Install membranes so that water drains over laps.

- Side and end laps [minimum): 75 mm. Fully seal.



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- Head and side laps: Offset.

• Successive layers: Do not trap moisture.

• Details: Weathertight. Form with adequate overlapping, staggering of laps and full bonding.

Laying single layer polymeric membrane:

• Adhesive bonding: Continuous even coating of adhesive. Do not wrinkle or stretch membrane.

• Surface condition at completion: Fully sealed, smooth, weatherproof and free draining.

Leadwork: In accordance with the Lead Sheet Association [LSAl publication ‘Rolled lead sheet. The complete manual’.

• Flashings generally:

- Thickness: Code 4 [1.75-2 mml.

- Lengths [maximum]: 1.5 m.

- End to end joint laps [minimum): 100 mm.

• Fixing into masonry bed joints: Secure with lead wedges.

Point up with mortar to match walling.



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10 ROOF DRAINAGE

1 MATERIALS AND COMPONENTS

Rainwater eaves gutters

Anodised Aluminium gutters: To BS 2997.

Rainwater flat roof outlets

Type: To suit pipework, with adaptors and connections recommended for the purpose by outlet manufacturer.

Rainwater pipework

Aluminium pipework: To BS 2997, or Agrement certified.

PVC-U pipework:

• External (unsealed] pipework: To relevant parts of BS 4576-1 and/ or BS EN 12200-1; Kitemarked.

• Internal [sealed] pipework: To relevant parts of BS EN 1329-1 or to BS 4514; Kitemarked.

Components

Ancillary items: From same manufacturer for each type of pipework and guttering.

2 EXECUTION

General

Execution generally: Lay rainwater goods to discharge rainwater completely, without ponding, leakage or noise nuisance.

Allowance for thermal and building movement: Provide and maintain clearance as fixing and jointing proceeds.

Gutters

Gutters laid to fall:

• Setting out: Set out gutters to true line and even gradient to prevent ponding or backfall. Position high points of gutters as close as practical

to the roof and low points not more than 50 mm below the roof.

• Joints: In direction of fall. Seal to make watertight.

Gutters laid level:

• Setting out: Level and as close as practical to roof.

• Joints: Seal to make watertight.

Pipework

Fixing: Fix securely, plumb and/ or true to line with additional supports as necessary to support pipe collars, particularly at changes in direction.

Internal pipework test:

• Preparation: Temporarily seal open ends of pipework with plugs. Fill traps.

• Testing: Connect a ·u’ tube water gauge and pump air into pipework until gauge registers 38 mm.

• Required performance: Allow a period for temperature stabilization, after which the pressure of 38 mm is to be maintained without loss for at

least 3 minutes.

• Water seal in traps throughout test (minimum): 25 mm.



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11 WOOD FLOORING AND LININGS 1 PRODUCTS

Particleboard Standard: To BS EN 312.

• Flooring: Type P5.

- Edges: Tongued and grooved.

- Joint adhesive: PVA to BS EN 204, class 03.

Plywood Flooring: Manufactured to the relevant standards and quality control procedures specified in BS 5268-2, and so marked.

• Edges: Tongued and grooved.

Timber boarding Flooring: To BS 1297.

• Face width [minimum): 113 mm.

- Long edges: Tongued and grooved. Linings: To BS 1186-3. Wood preservation and fire retardant impregnation treatment Preservative treatment: To British Wood Preserving and Dampproofing Association (BWPOA) Commodity Specification C8.

Fire retardant treatment:

• Linings: To BWPOA Commodity Specification FR1.

• Interior use in areas of relative humidity> 75%: To BWPOA Commodity Specification FR3.


Fasteners Nails: To BS1202-1 or to BS EN 10230-1.

• Material: Low carbon steel.

• Shank [minimum): - Flooring: 3.5 mm.

- Linings: 2 mm.

Screws: To BS 1210.

• Material: Brass or low carbon steel.

• Shank [minimum]: 8 gauge.


• Length:

- Flooring: Select length to penetrate 40 mm [minimum) into timber support.

- Linings: Select length to penetrate into timber support 25 mm [minimum) or to full thickness of ground/ batten.

2 EXECUTION Moisture content Moisture content of wood and wood based products at time of fixing: 9-13%.

Flooring Setting out board and sheet flooring:

• Long edges: Run across joists.

• End joints: Set out centrally over joists and stagger joints of adjacent boards or sheets.

• Expansion provision: Allow 10 mm clear expansion gap around floor perimeter.

Particleboard:

• Fixing to joists: Fix at 200 mm [maximum) centres around floor perimeter and along short edges of each board. Fix at 400 mm

[maximum) centres along intermediate supports.

• Fasteners: Annular ringed shank nails or wood screws.

• Joints: Glue with joint adhesive.

Plywood:

• Fixing to joists: Fix at 150 mm (maximum) centres around floor perimeter and along short edges of each board. Fix at 300 mm

[maximum) centres along intermediate supports.

• Laying over insulation: Do not mechanically fix through insulation.

• Joints: Glue with joint adhesive.

• Fasteners: Annular ringed shank nails or wood screws.

Timber boards:

• Fixing to joists: Two fasteners at each joist.

• Fasteners: Annular ringed shank nails, cut clasp nails or wood screws.



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Linings Wall linings:

• Grounds: Softwood.

- Size [minimum]: 20 x 15 mm.

- Setting out: Long edges vertical.

Setting out ceiling linings:

• Long edges: Run across joists.

• End joints: Set out centrally on joists and stagger joints of adjacent boards or sheets.

Particleboard and plywood:

• Fixing: Fix at 200 mm [maximum) centres along sheet edges. Fix at 400 mm [maximum) centres along intermediate supports.

• Fasteners: Wood screws.

Timber boards:

• Fixing: Two fasteners at each support.

• Fasteners: Lost head nails or wood screws.

Work to existing Removing existing flooring and linings:

• General: Carefully remove boards or sheets with minimum disturbance of adjacent flooring or linings.

• Undamaged boards and sheets: Set undamaged boards or sheets aside for reuse.



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12 PLASTERBOARD LININGS, PLASTERING, RENDERING AND SCREEDING Scope:


• Gypsum plasterboard backings, gypsum plasterboard and thermal board dry lining.

• Metal stud framing for wall linings and partitions.

• Insulation fitted between studs or ceiling joists in conjunction with linings.

• Plaster finishes (internal) to backing boards, masonry and lathing.

• Render finishes [internal and external} to masonry and lathing.

• Screed finishes to floors.

Related work:

• Timber joists, studs, battens, etc. to which linings are fixed - see section 06 'Structural timber and general carpentry'.

1 PRODUCTS

Gypsum plasterboard

Standard: To BS 1230-1.

Dry lining: Taper edge wallboard.

• Thickness [minimum): 12.5 mm.

Backing: Square edge or tapered edge wallboard.

• Damp and humid areas (kitchens, utility rooms, bathrooms): Moisture resisting wallboard.

• Thickness [minimum]: 12.5 mm. Plaster Gypsum plaster:

• Premixed lightweight undercoat plaster: To BS 1191-2.

• One coat, final coat and board finish plasters: To BS 1191-1, class B.

Renovating plaster [salt retardant): Agrement certified.

Cement Portland cement/ Portland slag cement: To BS EN 197-1.

Sulfate resisting cement: To BS 4027, Kitemarked.

Masonry cement: To BS EN 413-1.

Lime Type: Nonhydraulic to BS EN 459-1, type CL 90S.

Aggregate Fine aggregate:

• Rendering sand: To BS EN 13139.

- Grading: 0/2 or 0/4 [CP or MP) with category 2 fines.

• Screeding sand: To BS EN 13139.

- Grading limits: To BS 8204-1, table B1.

Coarse aggregate: To BS EN 12620.

- Dry dash or roughcast finish: Well washed.

Admixtures Water reducing admixtures: To BS EN 934-2. Admixtures containing calcium chloride: Not permitted.


Metal beads and stops Internal: Stainless steel or galvanized low carbon steel.

External: Stainless steel.

Metal framing for partitions and linings Type: Galvanized steel studs and channels to BS 7364.

Metal lathing

Steel lathing: To BS 1369-1.

• Lathing for plaster: Stainless steel or galvanized low carbon steel.

• Lathing for render: Stainless steel.



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Polyethylene membrane below unbonded or floating screed Thickness (minimum):

• Separation membrane: 250 µm [1000 gauge].

• Damp proof membrane [dpm]: 300 µm [1200 gauge], Agrement certified.

2 EXECUTION

Plasterboard

General:

• Joint widths [maximum]: 3 mm.

• End joints: Stagger between rows.

- Two layer boarding: Stagger joints between layers.

• Insulation fitted between studs or ceiling joists:

- Joints: Butt closely.

- Insulation between studs: Fasten to prevent slumping.

Plasterboard backings:

• Joints and angles: Apply joint reinforcement tape except where coincident with metal beads.

• Fixing centres [maximum]:

- Nails: 150 mm.

- Screws to partition and wall boards: 300 mm. Reduce to 200 mm at external angles.

- Screws to ceiling boards: 230 mm.

• Position of nails and screws from edges of boards (minimum):

- Bound edges: 10 mm.

- Cut or unbound edges: 13 mm.

• Position of nails and screws from edges of supports [minimum]: 6 mm.

• Nail and screw heads: Set below surface. Do not break paper or gypsum core.

Dry lining:

• Installation: In accordance with BS 8212.

• Finishing: Finish neatly giving flush, smooth, flat surfaces free from bowing and abrupt changes of level.

• Sealing gaps and air paths:

- Sealing: Apply sealant to perimeter abutments and around openings as a continuous bead with no gaps.

- Gaps between floor and underside of plasterboard: After sealing, fill with joint compound.

Plaster finishes Beads and stops:

• Location: External angles and stop ends.

• Fixing: Fix securely and true to line and level.

Undercoats:

• General: Apply coatings firmly and achieve good adhesion.

• Appearance of finished surfaces: Even and consistent. Free from rippling, hollows, ridges, cracks and crazing. Finish to a true

plane, with walls and reveals plumb and square.

• Drying out: Prevent excessively rapid or localized drying out.

• Keying undercoats: Cross scratch plaster coatings. Do not penetrate undercoat.

One coat plaster:

• General: Apply firmly and achieve good adhesion.

• Appearance of finished surface: Tight, matt, smooth surface with no hollows, abrupt changes of level or trowel marks. Finish

to a true plane, with walls and reveals plumb and square.

Plaster finish and board skim finish:

• Thickness: 2-3 mm.

• Appearance of finished surface: Tight, matt, smooth surface with no hollows, abrupt changes of level or trowel marks.

Render finishes Beads and stops:

• Location: External angles and stop ends.

• Fixing: Secure and true to line and level. Mechanically fix beads and stops for external render.

Application:

• General: Apply coatings firmly and achieve good adhesion.

• Appearance of finished surfaces: Even and consistent. Free from rippling, hollows, ridges, cracks and crazing. Finish to a true

plane, with walls and reveals plumb and square.

• Drying out: Prevent excessively rapid or localized drying out. Allow each coat to dry thoroughly, with shrinkage substantially

complete before applying next coat.

• Keying undercoats: Comb render coatings. Do not penetrate undercoat.

Render final coat:

• Dry dash: Achieve firm adhesion and an even overall appearance.

• Scraped finish: Scrape to expose aggregate. Achieve an even texture.



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• Plain floated finish: Even, open texture free from laitance.

Roughcast finish: Even thickness and texture.

Screeds

Preparation:

• Bonded screed: Key substrate. Apply bonding coat of polymer modified cement slurry.

• Un-bonded or floating screed: Lay polyethylene membrane over full area below screed and turn up at perimeter at least to full

depth of screed.

Mix:

• Cement: sand screeds: 1:3-4.5 cement: fine aggregate. Adjust mix to suit application.

• Fine concrete screeds for thin floor coverings: 1:4-5 cement: aggregate with aggregate proportions 75:25 fine aggregate:

coarse aggregate.

• Fine concrete screeds for ceramic tiles and bedding: 1:4-5 cement: aggregate with aggregate proportions 50:50 fine

aggregate: coarse aggregate.

• Water content: Minimum necessary to achieve full compaction.

Compaction:

• General: Compact thoroughly.

• Screeds over 50 mm thick: Lay in two layers of equal thickness. Roughen surface of compacted lower layer then immediately

lay upper layer.

Joints in levelling screeds: Lay continuously with ‘wet screeds’ between strips or bays. Minimize defined joints.

Permissible deviations from flatness (maximum) at any point on floor:

• Screeds to receive direct adhesive bedded sheet or tile finishes: 5 mm from underside of a 3 m straightedge and 2 mm under

a 1m straightedge.

• Screeds for flooring/ beds up to 50 mm thick: 10 mm from underside of a 3 m straightedge.

Finishes: Suitable to receive specified flooring material.

• Smooth floated: Even, with no ridges or steps.

• Trowelled: Uniform, smooth but not polished surface, free from trowel marks and other blemishes.

Curing: Prevent rapid water loss.

Work to existing Removing damp affected plaster:

• Plaster affected by rising damp: Remove to 300 mm above highest point reached by damp or 1 m above dpc, whichever is

higher.

• Mortar joints: Rake out.

• Drying out substrates: Allow free air flow over damp substrates.

Removing damaged plaster: Remove, except where damage limited to surface defects. Cut back to a square, sound edge.


Removing damaged render: Remove damaged render, except where damage limited to surface defects. Cut out to regular rectangular

areas with straight edges.

• Block lined render: Cut back to existing incised lines.

• Cracks wider than hairline: Cut out to a width of 75 mm (minimum).


Defective and salt contaminated masonry exposed by plaster or render removal:

• Isolated defective units or areas: Cut out and replace.

• Extensive defects: Notify.



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13 JOINERY, FINISHING CARPENTRY AND GLAZING

Scope:

This section covers carpentry, joinery and glazing fixed after completion of the building structure, including:

• Wood, metal and plastics doors and wood and plastics windows, including ironmongery and glazing for these items where these are to be site

fitted.

• Wood stairs and balustrades.

• Built-in furniture including kitchen fittings and built-in cupboards and wardrobes.

• Skirtings, architraves, window boards and other wood and wood based trim.

• Patent glazing fixed to steel or timber supports, including lead flashings.

• Joinery related elements of ancillary buildings, e.g. attached porches and conservatories.

Related work:

• Structural supports to patent glazing - section 05 'Steelwork' or 06 'Structural timber and general carpentry'.

1 PRODUCTS

Windows

Wood windows [purpose made] To BS 644.

• Timber: To BS EN 942, appearance class J40 generally, J10 for glazing beads, drip mouldings and the like.

Doors Fire doors and frames generally: Type tested to BS 476-22 or to BS EN 1634-1.

• In fire resisting construction in dwelling: Type FD20 or E20.

• Between dwelling and garage: Type FD30 or E30.

PVC-U doors: Agrement certified.

Security doorsets: To BS PAS 24-1, Secured by Design certified.

Ironmongery Design and fabrication: To BS 5268-3. Ironmongery to fire and smoke control doors:

• Hinges: Single axis hinges to BS EN 1935, CE marked.

• Overhead door closers: To BS EN 1154, CE marked.

Door locks [entrance and external doors] Five lever locks to BS 3621, Kitemarked.

Fasteners: Finish to match ironmongery.

Glazing Design: To BS 6262-2, -3 and -4. Glass: Generally to BS 952.

• Basic soda lime silicate glass: To BS EN 572.

• Coated glass: To BS EN 1096.

• Thermally toughened soda lime silicate glass: To BS EN 12150.

• Laminated glass: To BS EN ISO 12543.

Additional requirements for safety glazing: Classified in accordance with BS 6206.

Putty: To BS 544.

Patent glazing • Standard: To BS 5516-1.

• Glass: To BS 952 and relevant parts of BS EN 572, BS EN 1096, BS EN 12150 and BS EN ISO 12543.

• Double glazed units: To BS 5713 or to BS EN 1279.

• Plastics glazing sheets: To BS 5516-2, Annex A.

• Lead flashings: Rolled lead sheet to BS EN 12588.

Fasteners Screws: To BS 1210.


• Length [into supporting structure]:

- To timber supports: Full thickness of supporting timber or 40 mm [minimum].

- To supporting masonry [minimum): 63 mm.

• Shank:

- Masonry screws [minimum): 4.8 mm.

- Wood screws [minimum): 8 gauge.

Plugs for masonry fixings using wood screws: Size to match screws.

Wood and wood based trim Wood: Quality of wood and fixing to BS 1186-3. Medium density fibreboard (MDF): To BS EN 622-5.



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2 EXECUTION

General Surfaces of wood frames and trim inaccessible after installation: Prime or seal before fixing components.

Ironmongery, checking, adjusting and lubricating: Carry out at completion. Ensure correct functioning.

Glazing: In accordance with BS 8000-7.

Windows Fixing:

• Wood windows: Position fasteners not more than 150 mm from ends of each jamb, adjacent to each hanging point of opening

lights, and at 450 mm [maximum] centres.

Glazing installation [insulating units):

• Insulating unit: Locate centrally in surround with setting and location blocks and distance pieces.

• Inner sealant: Apply to full height of rebate.

• Outer sealant: Fill edge clearance void and space between unit and beads up to sight line.

• Finished thickness of back and front bedding after inserting glazing [minimum): 3 mm.

• Beads: Bed on outer sealant and fix securely. Trim excess sealant to a smooth chamfer.

Doors and frames • Fixing frames: Position fasteners not more than 150 mm from ends of each jamb, adjacent to each hanging point and at 600

mm [maximum) centres.

• Fire resisting frames: Fill gap between back of frame and reveal with plaster.

• Internal tape glazing: Bed glass and beads with glazing tape and fix securely. Trim tape flush on both sides.

Patent Glazing Execution generally: To BS 5516-1 and -2.

• Water penetration: Under site exposure conditions, water must not penetrate to the interior.

• Fixings: In accordance with system standard details, compatible with building components and substrate. Isolate dissimilar

metals to avoid electrolytic corrosion.

• Fabrication: Machine cut and drill components in the workshop wherever possible.

• Installation: Cut and drill into structural members only in agreed locations.

• Plastics glazing:

- Glazing bar edge cover to sheets: Sufficient to prevent displacement due to thermal movement and flexing under

load.

- Sealing and glazing materials: Compatible with sheets.

• Lead flashings: In accordance with the Lead Sheet Association [LSA) publication ‘Rolled lead sheet. The complete manual’.

• Apron flashing to patent glazed roofing at abutment:

- Lead: Code 5 [2.00 - 2.50 mm].

- Upstand [minimum): 75 mm.

- Cover to roofing [minimum): 220 mm for roof pitches from 20-300. 150 mm for roof pitches above 300.

- Fixing: Secure with lead wedges into bed joint. Clip bottom edge at laps and at 500 mm centres.

• Step and cover flashings to patent glazed roofing at raking side abutment:

- Lead: Code 4 [1.75 - 2.00 mm].

- Upstand [minimum): 85 mm.

- Cover to roofing [minimum]: Over end patent glazing bar and 150 mm onto glazing.

- Fixing: Secure with lead wedges at every course. Clip bottom edge at laps and at 500 mm centres.



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14 FLOOR AND WALL COVERINGS

Scope: This section covers:

• Rigid (natural stone, quarry and ceramic) tile coverings adhesive-bedded to floors and walls.

• Rigid wood or plastics (laminate) floor coverings.

• Resilient (rubber or vinyl) tile or sheet floor coverings.

• Carpet tiles and carpet roll floor coverings.

Related work:

• Concrete slabs directly finished to receive tiling - see section 03 'Concrete foundations and floors'.

• Plaster, render and screeds for tiling - see section 12 'Plasterboard linings, plastering, rendering and screeding’.

1 PRODUCTS

Underlays for floor coverings Rigid underlays for resilient flooring: Hardboard or plywood.

• Hardboard: To BS EN 622-2.

- Thickness (minimum): 3.2 mm.

• Plywood:

- Bonding quality: To BS EN 314-2.

- Thickness (minimum): 4 mm.

Resilient underlays for textile floor coverings: To BS 5808 and to BS EN 14499.

Resilient underlay for laminate flooring: As laminate manufacturer’s recommendation.

Polyethylene membrane below laminate flooring General: Agrement certified.

Thickness [minimum]:

• Separation membrane: 250 I-Im (1000 gauge).

• Damp proof membrane (dpm): 300 I-Im (1200 gauge).

2 EXECUTION General Drying times (minimum) for new substrates before application of coverings:

• Walls: Brick or block, 6 weeks; render coat, 2 weeks; gypsum plaster, 4 weeks.

• Floors: Concrete slabs, 6 weeks; screeds, 3 weeks. Plasterboard: Dry, securely fixed and rigid.

Setting out:

• Joints: True to line, continuous and without steps.

- Wall joints: Maintain alignment around corners.

- Floor joints: Parallel to main axis of space.

• Cut tiles: Minimize number, maximize size and locate unobtrusively.

- Cutting: Neat and accurate.

- Waste: Retain suitable covering material for patching. On completion, hand over to customer.

Rigid sheet floor coverings Laminate flooring: Spacer blocks and debris: Remove before fixing skirtings.

Resilient tile floor coverings Setting out: Set out with tiles along opposite edges of equal size and at least half of full tile width.

Work to existing Existing substrates generally:

• Dirt and other loose material: Remove and make good with materials compatible with substrate.

• Deposits of oil, grease and other materials incompatible with the bedding: Remove.

• Tiled, painted and other nonporous surfaces: Clean.

• Wet substrates: Dry before tiling.

• Paint with unsatisfactory adhesion: Remove.

• Plaster which is loose, soft, friable, badly cracked affected by efflorescence: Remove. Cut back to straight horizontal and

vertical edges, slightly undercut. Make good with plaster or nonshrinking filler.



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15 DECORATIONS Scope:

This section covers preparing and sealing surfaces and decorative and protective painting, staining, varnishing and papering.

1 PRODUCTS Paints and primers Undercoats and finishing paints: To BS 7664.

Aluminium primers for resinous wood: To BS 4756.

Primers for wood: To BS 7956.

Coating systems for exterior wood: To BS EN 927.

Coating systems for exterior masonry: To BS EN 1062.

Biocides Biocides: Listed in British Health and Safety Executive (HSE) ‘Pesticides’, Part B, as surface biocides.

2 EXECUTION

Preparation generally • Preparation: In accordance with BS 6150.

• Substrates: Sufficiently dry in depth to suit coating. Efflorescence salts, dirt, grease, oil, corrosion, loose and flaking material:

Remove.

• Surface irregularities (including plaster nibs, trowel marks and splashes): Abrade to a smooth finish. Lightly round arrises.

Joints, cracks, holes and other depressions: Fill with stoppers or fillers. Abrade to a smooth finish. Remove residues.

• Existing fixtures, fittings and ironmongery: Remove before commencing work. Refurbish as necessary, refit when decoration

is dry.

• Doors, opening windows and other moving parts: Ease if necessary before coating. Prime resulting bare areas.

• Wood resinous areas and knots: Apply two coats of knotting.

Coatings • Priming coats: Apply as soon as possible on same day as preparation is completed.

• Concealed joinery surfaces: After priming, apply additional coatings to surfaces that will be concealed when component is

fixed in place.

• Finish: Even, smooth and of uniform colour. Free from brush marks, sags, runs and other defects. Cut in neatly.

• Bead glazing to coated timber: Apply first two coats to rebates and beads before glazing.

• Putty glazing: Within 21 days, seal with an oil based primer. Extend finishing coats on to glass up to sight line.



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16 EXTERNAL PAVING AND DECKING

Scope:


• Hardcore sub-bases to pavings .

• In situ concrete paving, macadam paving, interlocking unit paving, brick, flag and slab paving and gravel paving.

• Timber decking.

• 1 PRODUCTS

Hardcore sub-bases to pavings Fill: Clean granular material, free from harmful matter and excessive dust and clay, well graded, passing a 75 mm BS sieve, comprising

one of:

• crushed hard rock and/ or quarry waste;


• gravel and/ or hoggin.

In situ concrete for paving

Standards: To BS EN 206-1 and BS 8500-2. Designated concrete: Type PAV1.

• Aggregate size [maximum]: 20 mm.

• Use of recycled aggregates: Permitted.

- Temperature range of concrete at delivery: 5-30°C.

• Admixtures containing calcium chloride: Not permitted.

Sundry items for in situ concrete paving

Separation membrane: Polyethylene.

• Thickness [minimum]: 250 IJm [1000 gauge].Fabric reinforcement: To BS 4483.

• Tying wire: 16 sW.g. [1.63 mm] black annealed.

Kerbs, edgings and channels Precast concrete kerbs, edgings and channels: To BS EN 1340. Natural stone kerbs: To BS EN 1343.

Bricks for kerbs: To BS 3921.

• Type: Solid, designation FL.

Timber edgings to gravel or macadam pavings:

• Softwood board: 38 x 150 mm.

• Softwood pegs: 50 x 50 x 600 mm long.

• Preservative treatment: To British Wood Preserving and Damp-proofing Association (BWPDA] Commodity Specification

C3. CCA treatment not permitted.

Gravel for pavings Type: Crushed quarried rock or naturally occurring material from gravel beds.

• Grading: Hoggin and hard binding gravel to contain sufficient fine material for consolidation.

Macadam Coated macadam: To BS 4987-1.

Unit pavers Natural stone slabs: To BS EN 1341.

Natural stone setts and cobbles: To BS EN 1342.

Sand and mortar • Cement: To BS EN 197-1, Portland CEM 1.

• Sand for mortar: To BS EN 13139,0/4 [grading limit MPI. fines category 1.

• Bedding sand: Naturally occurring clean sharp sand.

• Jointing sand: To BS EN 12620, grading limit MP or FP.

Softwood framing to timber decking • Grading standard: To BS 4978 and/ or BS EN 519.

• Strength class: To BS EN 338, class C16 [minimum].

• Preservative treatment: To BWPDA Commodity Specification C3. CCA treatment not permitted.



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2 EXECUTION

General Hardcore sub-bases to pavings:

• Subgrades: Excavate to formation level in dry conditions immediately before compaction. Fill general soft spots and voids.

- Compaction: Adequate to resist subsidence and deformation during construction and of the completed paving when

in use. Compact fully at intrusions, perimeters and where local excavation and backfilling has taken place.

- Compacted surface: Well closed, no movement under compaction plant. Without cracks, holes, ridges, loose

material or the like.

• Sub-bases:

- Preparation: Remove loose material, rubbish and standing water.

- Laying: Spread, level and compact fill material in 150 mm [maximum] layers. Each layer to contain only one of the

‘permitted material’ types.

- Compaction: Compact as soon as possible after laying, sufficient to resist subsidence and deformation of the

completed paving when in use.

• Permissible deviation [maximum] from required levels, falls and cambers: Subgrade ± 20 mm, sub-base ± 12 mm.

• Protection: As soon as practicable, cover with subsequent layers.

Precast concrete kerbs and edgings:

• Laying generally:

- Cutting units: Cut neatly and accurately without spalling. Form neat junctions.

- Bedding and backing of units: Bed on 1:3 cement: sand: mortar laid on hardened concrete base. Secure units with

a continuous haunching of concrete.

- Mortar bedding thickness: 12-40 mm.

• Deviations [maximum]: Level, ± 6 mm. Horizontal and vertical alignment, 3 mm in 3 m.

• Tooled mortar joints: Butter ends of units with bedding mortar as laying proceeds. Fill joints completely and tool to a neat flush

profile.

- Joint width: 6 mm.

Timber edgings: Drive softwood pegs into ground at 1.2 m centres. Fix boards to pegs with galvanized nails.

Pavings generally:

• Cutting units: Cut neatly and accurately without spalling. Form neat junctions.

• Laying generally:

- Preparation: Remove loose material, rubbish and standing water. -Adjacent work: Form neat junctions.

- Lines and levels of finished surface: Smooth and even with falls to prevent ponding.

• Deviations [maximum):

• Concrete and macadam: Finished surface generally, ±6 mm. Level adjacent to gullies and manholes, 0 to + 3 mm.

• Unit pavings: Finished surface generally, ±6 mm. Level adjacent to gullies and manholes, +6 to 10 mm; adjacent to drainage

channels and tops of kerbs, +3 to 6 mm.

Macadam paving Execution generally: To BS 4987-2.

• Protection: Exclude traffic until paving has cooled to prevailing atmospheric temperature.

• Overall texture: Smooth, even and free from dragging, tearing or segregation.

Brick, flag or slab paving Laying: Lay units on 25 mm semidry full mortar bed.

• Bedding of units: Firm so that rocking or subsidence does not occur or develop.

• Appearance: Even and regular with even joint widths and free of mortar and sand stains.

• Protection from traffic: After laying keep free from pedestrian traffic for 4 days.

Dry mortar joints:

• Execution: When paving is dry and rain is not expected.

• Jointing: Brush dry mortar into joints and ram firmly home until joints are filled solid and flush. Brush off residue. Allow joints to

hydrate naturally.

• Protection: After filling joints, protect from rain for 3 days [minimum].



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17 TOPSOILING AND EXTERNAL PLANTING

Scope:


• Topsoiling: Reuse of undisturbed topsoil. Procurement, spreading and handling of imported topsoil.

• Grass turfing and seeding.

• Tree and shrub planting.

1 PRODUCTS

Imported topsoil Grade: General purpose to BS 3882, reasonably free of stones and with no clods larger than 50 mm in any dimension.

Compost for topsoil amelioration Compost: In accordance with BS PAS 100.

Type: Friable sanitized and stabilized compost.

Grass Seed: Seed produced for the current growing season.

• Certification: DECO Grass and legume seed scheme.

• Category: Certified seed.

Turf: Free from undesirable grasses and weeds.

• Supplier: A member of the Turfgrass Growers Association.

Trees and shrubs Standard: To BS 3936-1, -4 or -5 or to the National Plant Specification.

Condition: Sturdy, healthy and vigorous, of good shape and without elongated shoots.

Container grown plants Condition: Plants centred in containers, firmed and well watered. Roots substantially filling containers but not root bound, and in a

condition conducive to successful transplanting.

2 EXECUTION Preparation for planting

Topsoil:

• Compacted soil: When ground conditions are suitably dry, loosen, aerate and break up soil to particles of 2-8 mm.

• Undesirable material: Remove weeds, roots, stones, clods larger than 50 mm, tufts of grass and foreign matter.

• Spreading topsoil: Spread in 150 mm layers (maximum before firming] when reasonably dry. Gently firm each layer before

spreading the next. Do not compact.

• Depths after firming and settlement (minimum):

- Areas to be grassed, 100 mm.

- Areas to be planted, 450 mm.

Within root spread of existing trees: Do not cultivate.

Planting supports:

• Single staking: Drive vertically at least 300 mm into the base of the pit before planting. Consolidate backfilling material around

the stake as filling proceeds.

- Height: Approximately 600 mm above ground level.

- Tying: Secure tree firmly but not rigidly to stake within 25 mm of top of stake.

Planting Climatic conditions: Do not plant during periods of frost, strong winds or heavy rain.

Grass seeding and turfing:

• Fertilizing: Before final cultivation and 3-5 days before seeding / turfing.

• Final cultivation: Reduce to fine, firm tilth with good crumb structure. Depth, 25 mm (minimum).

- Surface preparation: Rake to a true, even surface.

- Adjacent levels: Extend cultivation into existing adjacent grassed areas to ensure full marrying in of levels.

- Surface stones and earth clods: Remove those exceeding 20 mm (10 mm for fine lawns).

• Watering: Soak the full depth of topsoil. Water evenly.

• Seeding:

- Sowing: Good seed contact with the soil. Method of sowing to suit soil type and weather conditions.

- Watering: Full depth of topsoil. Water evenly.

• Turfing:

- Timing: Lay as soon as possible after lifting.

- Adjusted levels of beds: Rake out high spots. Fill hollows.

- Laying turfs: Lay with broken joints, well butted up. Do not stretch turf. Form edges of laid areas with whole turfs



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trimmed to a true line. Brush in dressing to fill joints.

- Consolidation: Lightly and evenly as work proceeds. Achieve full contact with substrate. Do not use rollers.

- Watering: Water full depth of newly laid turf and topsoil.

Trees and shrubs:

• Planting: In pits so crown of rootbaLL is at ground level.

- Pruning: Trim by one-third. Leave a well balanced head.

General planting:

• Bulbs, corms and tubers: Set top at a depth of approximately twice height and base in contact with bottom of hole.

• Climbing plants: Locate 150 mm clear of supporting structure (e.g. wall or fence] with roots spread outward. Lightly secure

branches to supports. Retain canes of plants which are too small to reach supports.

Maintenance Beds and bases of hedges: Keep free of weeds.

Pathogens: Keep plants free of pests and diseases.

Cultivation: Fork over beds as necessary to keep soil loose.

Staking: Check and adjust stakes, ties, guys and guards. Replace broken or missing items.

Watering: Water until full depth of topsoil is saturated.

- Frequency: As required to provide healthy growth.

Pruning: Trim with a clean smooth cut to a main stem or a sound and healthy outward growing lateral.

- Timing: Prune at appropriate times, to promote healthy growth and natural shape,

Maintenance of grass areas: In accordance with BS 7370-3.

• Grass cutting:

- Preparation: Before each cut remove litter and debris.

- Cutting: As necessary to a height of 25 mm. Remove arisings.

- Bulb planting areas: Do not cut until bulb foliage has died down.

- Trimming: All edges. Remove arisings.

- Weed control: Substantially free of broad leaved weeds.

- Stones: Remove stones exceeding 25 mm in any dimension,

• Grass fertilizer:

- March application: 15:10: 10 spring turf fertilizer at 35 g/m2.

- September application: 5:10:10 autumn turf fertilizer at 50 91m2.

Instructions: Before end of maintenance, submit instructions for procedures to be established by the customer for one year’s

maintenance.



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18 FENCING AND GARDEN WALLING

Scope: This section covers common types of wood or metal boundary fencing and gates, and masonry garden walling.

Related work:

Concrete foundations - see section 03 'Concrete foundations and floors'.

1 PRODUCTS

Wood fencing

Chestnut pale fencing: To BS 1722-4.

Close boarded and wood palisade fencing: To BS 1722-5.

Post and rail fencing: To BS 1722-7.

Prefabricated wood panel fencing: To BS 1722-11.

Metal fencing Chain link: To BS 1722-1.

Steel vertical bar: To BS 1722-9.

Gates and posts Wood [purpose made gates): To BS 5709.

• Adhesive: Synthetic resin to BS EN 301, type 1.

Preservative treatment to wood fencing and gates Standard: To British Wood Preserving and Damp-proofing Association [BWPDA) Commodity Specification C3. CCA treatment not

permitted.

Cements, Lime and Aggregates

Portland cement: CEM I to BS EN 197-1.

Sulfate resisting cement: To BS 4027, Kitemarked. Ready mixed lime/ sand: To BS EN 998-2.

• Lime: Nonhydraulic to BS EN 459-1. Type, CL 90S. Fine aggregate: To BS EN 13139.

• Grading for mortar sand: 0/2 (FP or MP) with category 3 fines content.

Coarse aggregate: To BS EN 12620. Size (maximum): 20 mm.

Fasteners Nails: To BS 1202-1 orto BS EN 10230-1.

• Material: Galvanized low carbon steel.

• Shank (minimum): 3.5 mm.

• Length: To penetrate 40 mm (minimum) into timber support.

Garden walling Clay bricks: To BS 3921 or to BS EN 771-1.

Manufactured stone blocks: To BS 6457 or to BS EN 771-5.

Cast stone dressings and other components: To BS 1217.

Natural stone: Thoroughly seasoned and free from cracks, vents, fissures or other defects deleterious to strength, durability or

appearance.

Rubble stone quoins and jambs: Large stones dressed to a regular shape.

Ties between butt jointed masonry leaves: To BS EN 845-1. Material: Austenitic stainless steel.

Flexible dpcs:

• Bitumen based: To BS 6398.

• Lead: Rolled sheet to BS EN 12588.

• Other materials: Agrement certified.

Rigid dpcs:

• Natural slate: To BS EN 12326.

• Clay damp proof course bricks: To BS 3921 or to BS EN 771-1.



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2 EXECUTION

Garden walling

Basic brickwork:

• Mortar joints: Lay units on full bed. Fill vertical joints.

• Lift height [maximum): 1.2 m above other parts of work but not more than 1.5 m daily.

Basic rubble stonework: Lay units on full bed. Fill voids and vertical joints. Avoid long continuous vertical joints. Facework:

• Lowest courses: At least 150 mm below finished ground.

• Appearance and coursing: Plumb with consistent appearance.

• Cleanliness: Keep units clean.

Horizontal dpcs (flexible): Lay on full mortar bed. Lap 100 mm [minimum) at joints and fully lap at angles.

• Width: At least full width of masonry leaf.

• Overlying construction: Full even bed of mortar to receive next masonry course.

• Ground level dpcs: At least 150 mm above finished ground.

Work to existing

Garden walling alterations:

• Coursing: Line up with existing work.

• Bonding of new walls to existing: Bond at every course to achieve continuity of bond and coursing.

• Forming openings in existing walling: Finish ends of runs with staggered half and whole masonry units.

• Repainting masonry walling:

• Preparation: Cut out joints to 15-20 mm depth. Clean and dampen joints sufficiently to control suction.

• Cracked units in existing facework: Cut out and replace with matching masonry before repainting.

• Joint profile: Match existing.

• Jointing mortar: 1:1:6 cement: lime : sand.



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19 DRAINAGE BELOW GROUND Scope:


• Below ground foul drainage, surface water drainage and subsoil drainage. • Access chambers and disposal systems. •

1 PRODUCTS

General Access covers and seating: Grey or ductile iron to BS EN 124.

• Loading grades to BS EN 124:

- Areas inaccessible to vehicles: A 15.

- Drives or footpaths adjacent to drives: B 125.

Granular bedding material: To BS EN 12620, size 4/10.

In situ concrete: To BS EN 206-1 and to BS 8500-2.

• Mix: Designated concrete GENl or Standardized prescribed concrete ST2. Drainage Pipework and fittings Foul drainage and surface water drainage:

• Clay pipes, bends and junctions: Vitrified clay to BS EN 2951, with flexible joints, Kitemarked.

• Plastics pipes, bends and junctions: PVC-U to BS EN 14011, class SN4, Kitemarked.

• Gullies:

- Clay: To BS EN 295-1, Kitemarked; or Agrement certified.

- Plastics: To BS 4660, Kitemarked; or Agrement certified.

Land drainage:

• Perforated clay pipes, bends and junctions: Vitrified clay to BS EN 295-5. Size, ON 100.

• Perforated plastics pipes, bends and junctions: PVC-U to BS EN 1401-1, class SN4 or SN8 with flexible joints, Kitemarked.

Size, ON 110.

Silt traps:

• Clay: To BS EN 295-1, Kitemarked; or Agrement certified.

• Concrete: To BS 5911-6, Kitemarked; or Agrement certified.

• Plastics: To BS 4660, Kitemarked; or Agrement certified.

Access chambers Access points [plastic mini-chambers]: To BS 4660 and Kitemarked, or to BS EN 13598-1, or Agrement certified.

Brick manholes and inspection chambers:

• Clay engineering bricks: To BS 3921 or to BS EN 771-1.

• Steps: Galvanized steel to BS EN 13101.

- Chamber depth less than 900 mm: Steps not required.

• Reinforcement: Steel fabric to BS 4483.

Disposal Private packaged septic tank units: To BS EN 12566-1, or Agrement certified.

• Inlet and outlet pipes: Material and standard as foul drainage pipework generally. Size, ON 100 or ON 110.

• Vent pipes: PVC-U to BS EN 1401-1, class SN4, Kitemarked. Size, ON 110.

Granular fill soakaways:

• Silt barrier: Geotextile membrane.

• Vertical inspection/ and distributor pipes: PVC-U, ON 225, perforated.

• Granular material: Clean broken bricks, crushed rock or gravel, size range 50-150 mm.

2 EXECUTION

Discrepancies Existing drains: Before starting work, check levels and positions of existing drains, inspection chambers and manholes against

drawings. Report discrepancies.

Drainage

Pipework and fittings Excavating pipe trenches:

• Trench from bottom up to 300 mm above crown of pipe: With vertical sides.

- Width: As small as practicable but not less than external diameter of pipe plus 300 mm.

• Timing: Excavate to formation immediately before laying beds or pipes.



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• Mud, rock projections, boulders and hard spots: Remove. Replace with bedding material, well consolidated.

• Local soft spots: Harden by tamping in bedding material. Bedding and jointing:

• Laying pipes: To true line and regular gradient on even bed for full length of barrel with sockets (if any) facing up the gradient.

Cut/ scoop out locally at couplings and sockets and lay pipes digging slightly into bed and resting uniformly on their barrels.

Adjust to line and gradient.

- Hard packings under pipes: Do not use.

• Jointing: Lubricate. Leave gaps at ends of spigots to allow for movement.

Trench types for vitrified clay pipelines:

• Trimmed natural trench base:

- Application: Use for bedding of flexible sleeved plain wall clay pipes only if natural trimming by shovel is possible.

- Trench base: Hand trim to accurate levels, levelling up any overdig with compacted spoil.

- Preliminary backfilling: After initial testing of pipeline, backfill to 150 mm [minimum) above crown of pipe with a

protective cushion of selected fill, free from vegetable matter, rubbish and frozen soil and material retained on a 40

mm sieve. Thoroughly hand compact in 100 mm layers.

• Granular bedding:

- Application: Use for granular bedding of flexible sleeved plain wall clay pipes.

- Bedding: 150 mm [minimum) compacted granular material.

- Preliminary backfilling: After initial testing of pipeline, backfill to 150 mm [minimum) above crown of pipe with a

protective cushion of selected fill, free from vegetable matter, rubbish and frozen soil and material retained on a 40

mm sieve. Thoroughly hand compact in 100 mm layers.

Trench types for plastics pipelines:

• Granular bed and side fill:

- Application: Use for granular bedding and support to plastics pipes.

- Bedding: 100 mm [minimum) compacted granular material.

- Granular support: After initial testing of pipeline, lay and compact by hand more granular material uniformly to 100

mm above crown of pipe.

• Granular surround:

- Application: Use for plastics pipes under solid ground floors with cover depth of 300 mm or more.

- Timing: Excavate trench after hardcore has been laid and compacted.

- Bedding: 100 mm [minimum] compacted granular material.

- Granular surround: After initial testing of pipeline, lay and compact by hand granular material to 100 mm above

crown of pipe.

- Backfilling: Compact hardcore or granular material in layers not exceeding 300 mm thick up to slab formation.

Concrete surround:

• Application: Use for plain wall clay or plastics pipes laid close to, and below level of, existing foundations.

• Concrete blinding: 25 mm thick, over full width of trench.

• Temporary pipe support: Lay folding wedges of compressible board to support pipeline 100 mm [minimum) above blinding.

• Vertical construction joints: Apply sections of 18 mm thick compressible board, cut out to pipe size, at flexible pipe joints

positions. Extend board to full width and depth of concrete surround.

• Concrete surround: After initial testing of pipeline, place and compact concrete for full width of trench to encase pipe to 150

mm above crown, or to adjacent foundation level, whichever is higher.

Trench types [bedding classes) for subsoil drainage perforated pipelines:

• Granular surround for groundwater: For use with perforated pipes, e.g. in conjunction with filter drains to provide water

pressure relief drainage behind retaining walls.

- Bedding: Granular material, 75 mm deep, at least 100 mm wider than pipe.

Granular surround: Compact to 150 mm above pipe.

Additional protection to pipelines at shallow depth in cultivated ground: Lay concrete paving flags 100 mm clear above pipes as

additional protection.

Bends at base of soil stacks:

• Bends: 90° nominal rest bend with a minimum radius of 200 mm to centreline of the pipe.

• Height of invert of horizontal drain at base of stack below centreline of lowest branch pipe [minimum): 450 mm.

• Stabilizing bends: Bed in concrete without impairing flexibility of couplings.

Installation of fittings:

• Appearance: Square with and tightly jointed to adjacent construction as appropriate.

• Bedding and surround of fittings, traps, etc: Concrete, 150 mm thick.

- Deviation in level of gullies: +0 to -10 mm.

Completion of backfilling to pipeline trenches generally:

• Backfill from top of surround or protective cushion with material excavated from trench. Compact in 300 mm layers. Do not

use heavy compactors where there is less than 600 mm of material over pipes.

Completion of backfilling under roads and pavings:

• Backfill from top of specified surround or protective cushion up to formation level with well graded gravel or hardcore passing

a 75 mm sieve. Compact in 150 mm layers.



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Access chambers Brick inspection chambers:

• Bases: 150 mm [minimum) plain in situ concrete.

• Wall thickness: 215 mm.

- Bricks: Lay with frogs facing upwards.

• Steps: Bed in joints to chambers over 900 mm deep at 300 mm vertical centres staggered 300 mm horizontally, with top step

not more than 450 mm below top of cover.

• Conventional channels, branches and benching:

- Main channel: Bed solid in 1:3 cement:sand mortar.

Connect branches to main channel at half channel level, so that discharge flows smoothly in direction of main flow.

- Benching: Place concrete to rise vertically from main channel to a height not lower than soffit of outlet pipe, then

slope upwards at 10% to walls. Trowel to dense smooth uniform finish.

• Cover slabs: 150 mm (minimum) in situ concrete.

- Openings: To suit required access covers.

• Bedding and haunching to access covers: Solid, in 1:3 cement: sand mortar, square with joints in surrounding finishes. Cut

back top of haunching to 30 mm below top of cover.

Completion and testing Testing and inspection generally: Remove obstructions and debris. Check that the installation is clear before testing. Time before initial

and final testing:

• Cement mortar jointing: Leave 24 hours.

• Solvent welded pipelines: Leave 1 hour.

Initial testing of pipelines: Block open ends of pipelines to be tested and pressurise. Air test short lengths to BS EN 1610.

Final testing of drains: In accordance with DOE Building Regulations Part H, clause 1.3.26 [air / water test].

Water testing of manholes and inspection chambers:

• Timing: Before backfilling.

• Standard:

- Exfiltration: To BS EN 1610, method W.

- Infiltration: No identifiable flow of water penetrating chamber.

Cleaning: Flush out the whole installation and remove silt and debris immediately before handing over.



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20 PLUMBING SYSTEMS

Scope:

This section covers sanitary appliances and fittings, above ground foul drainage pipework, hot and cold water installations and domestic

sprinkler systems.

Related work:

• Gas installation - see section 21 'Mechanical systems'.

1 COMPLETION OF DESIGN

Design requirements

Incoming water supply design:

• Capacity: Determine the anticipated maximum demand of the installation.

• Establishing the supply: Manage and liaise with the water company to establish an incoming supply.

• Incoming earth bonding arrangement: Establish with the water company.

• Location: Coordinate the location of the incoming supply. Water distribution:

• Design: Complete the design of the hot and cold water supply system.

- Standard: To BS 6700 or to BS EN 806-2 and -3.

Above ground foul drainage system:

• Design: Complete the design of the above ground drainage pipework.

- Standard: To BS EN 12056-2.

Domestic sprinkler system:

• Design: Complete the design of the sprinkler pipework. - Design: In accordance with BS 9251.

- Reliability: Ensure reliability and continuity of water supplies.

Proposals: Submit drawings [showing equipment positions and pipeline routes], technical information, calculations and manufacturers’

literature.

2 PRODUCTS

Sanitary appliances:

• WC suites: To DEFRA ‘WC suite performance specification’, or approved by water company.

• Wastes and traps: To BS EN 274-1, -2 and -3.

• Depth of water seal (minimum): Basins, bidets and sinks, 75 mm; baths and showers, 50 mm.

• Cistern operating components: Match to pressure of water supply.

Above ground foul drainage system

Branch waste pipework:

• MUPVC: To BS 5255.

• PVC-C: To BS EN 1566-1.

• Polypropylene: To BS 5255 or to BS EN 1451-1.

Soil vent pipework and WC branches:

• PVC-U: To BS EN 1329-1, Kitemarked, or to BS 4514, Kitemarked.

• Cast iron: To BS EN 877 with flexible joint couplings.

•Air admittance valves: To BS EN 12380 or Agrement certified.

Hot and cold water system Water fittings: CE marked, or conforming to a specification approved by the water regulator.

Instantaneous shower units, electric: To BS EN 60335-2-35, BEAB approved.

Direct hot water storage cylinders: To BS 1566-1, Kitemarked. Direct insulated combination units: To BS 3198, Kitemarked. Unvented

hot water storage: To BS 7206.

Indirect hot water storage cylinders:

• Double feed: To BS 1566-1, Kitemarked. • Single feed: To BS 1566-2.

• Indirect insulated combination units: To BS 3198, Kitemarked. Copper pipelines:

• General use: To BS EN 1057, Kitemarked.

• Underground use: To BS EN 1057, Kitemarked.

- Finish: Seamless polyethylene to BS 3412.



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• Exposed connections to appliances: Chrome plated.

• Polyethylene pipelines for underground use: To BS 6572, Kitemarked; or to BS EN 12201-2 and -3.

• Thermoplastics pipelines: To BS 7291.

Fittings, pipelines, equipment located below ground or in concealed or inaccessible locations: Resistant to dezincification, e.g.

gunmetal.

Insulation to pipelines:

• Material: Flexible closed cell or mineral fibre split tube.

• Thickness:

- Hot water pipelines: Equal to the outside diameter of the pipe up to a maximum of 40 mm.

- Internal cold water pipelines: 25 mm.

- Roof space cold water pipelines: 32 mm.

- External cold water pipelines: 38 mm.

• Fire performance: Class 1 spread of flame when tested to BS 476-7.

EXECUTION General Concealed or inaccessible surfaces: Decorate before installing plumbing systems.

Pipeline installation:

• Appearance: Install pipes straight, and parallel or perpendicular to walls, floors, ceilings, and other building elements. Fix

securely and neatly.

• Joints, bends and offsets: Neat, clean and fully sealed. Do not use formed bends on exposed pipework, except for small

offsets. Form changes of direction with radius fittings.

• Pipelines finish: Smooth, consistent bore, clean, free from defects.

• Concealment: Generally conceal pipelines within voids.

• Access: Locate runs to facilitate installation of equipment, accessories and insulation and allow access for maintenance.

• Electrical equipment: Install pipelines clear of electrical equipment.

• Drains and vents: Fix pipelines to falls. Fit draining taps at low points and vents at high points.

• Thermal expansion and contraction: Allow for thermal movement of pipelines. Isolate from structure. Prevent noise or

abrasion of pipelines caused by movement. Sleeve pipelines passing through building elements.

Fixing of equipment, appliances, components and accessories: Fix securely to structure, parallel or perpendicular to the structure of the

building.

Preparation: Immediately before installing sanitary fittings, tanks or cisterns on a floor or platform, clear the surface completely of debris

and projections.

Corrosion resistance: In locations where external moisture is present or may occur, provide corrosion resistant fittings/ fixings and avoid

contact between dissimilar metals by use of suitable washers, gaskets, etc.

Jointing and bedding compounds: Recommended by manufacturers of components being jointed or bedded.

Pipeline spacing:

• Clearance [minimum] to face of wall-fixed pipes or insulation:

- From floor: 150 mm.

- From ceiling: 50 mm.

- From wall: 15 mm.

- Between pipes: 25 mm.

Insulation to pipelines: Fix securely and neatly. Make continuous over fittings and at supports. Leave no gaps. Locate split on ‘blind’ side

of pipeline.

Sanitary appliances Standard: To BS 6465-1.

• Assembly and fixing: Generally level and plumb. Surfaces designed to fall to drain as intended.

Above ground foul drainage system

Standards: To BS EN 12056-2 and to BS EN 12056-5.

Drainage from appliances: Quick, quiet and complete, without blockage, backfall, leakage, noise nuisance or risk to health.

Access: Provide access fittings in convenient locations to permit cleaning and testing of pipework.

Discharge stack pipes: Fix at or just below socket collar or coupling. Provide additional support as necessary at junctions and changes

in direction.

Hot and cold water system Standard: To BS 6700.

Insulation to cisterns: Insulate underside of cistern where exposed in unheated spaces.

Isolation and regulation valves: Provide on equipment and subcircuits.

Completion and testing Above ground foul drainage system:



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• Preparation: Temporarily seal open ends of pipework using plugs.

• Testing: Connect a ‘U’ tube water gauge and pump air into pipework until gauge registers 38 mm.

• Required performance: Allow a period for temperature stabilization, after which the pressure of 38 mm is to be maintained

without loss for at least 3 minutes.

Hot and cold water system:

• Flushing, filling and disinfection: To BS 6700.

• Testing: To BS 6700.

- Notice (minimum): 3 days.

- Commissioning: To BS 6700.

Domestic sprinkler system:

• Flushing: Flush out debris via the flushing valves.

• Testing system:

- Notice [minimum]: 3 days.

- Static pressure test: Charge the system to 1500 kPa. Maintain for 1 hour. During this period, inspect the system to

check that no water leaks at joints or valves.

• Water supplies: Test in accordance with BS 9251.

Documentation and tools:

• Operating and maintenance instructions: Submit copies of manufacturers’ operating and maintenance instructions for

equipment and controls.

• Record drawings: Submit drawings showing the location of circuits and operating controls.

• Tools: Supply tools for operation, maintenance and cleaning purposes, including keys for valves and vents.



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21 MECHANICAL SYSTEMS Scope:

This section covers mechanical installations where the design work is to be completed by the contractor and includes:

• Gas installation.

• Low temperature hot water heating for domestic buildings requiring a single boiler.

• Gas fires and wood fired roomheaters.

• Natural and simple mechanical ventilation for domestic buildings, including simple 'standalone' mechanical ventilation units, e.g. extract

fans, ducted mechanical ventilation systems, passive ventilation ducts from outside to inside and passive stack ventilation systems.


Design requirements

Incoming gas supply design:

• Capacity: Determine the anticipated maximum demand of the installation. • Establishing the supply: Manage and liaise with the gas distributor to establish an incoming gas supply.

• Incoming earth bonding arrangement: Establish with the gas distributor.

• Location: Coordinate the location of the incoming supply and establish the spatial requirements for the gas distributor's

equipment and metering.

Gas/ oil distribution system: Complete the design of pipelines.

Low temperature hot water heating system:

• Design: Complete the design and detailing of the heating system.

• Temperature and time control: Fully automatic and independent.

• Heating system heat loss calculations: Calculate for each room. Submit U-value calculations for fabric on which heat loss

calculations are based.

Natural and mechanical ventilation system: Complete the design of the ventilation systems to provide ventilation rates contained in DOE

Building Regulations Part F.

Design information: Submit calculations, manufacturer's literature and drawings showing equipment positions and pipework/

ductwork routes.

2 PRODUCTS

Gas installation Safety and control devices: To BS EN 13611.

Domestic low pressure gas supply pipelines: To BS 6891.

Gas plug cocks: To BS 1552.

Gas ball valves: To BS EN 331.

•

Heating system - heating source Gas fired boiler: Condensing boiler to BS EN 677.

Wood burning stove: To BS 7256.

Heating system - heat emitters Underfloor heating system to ground floor and extension area, Unipipe or similar approved to manufacturers design and installation

requirements.

Existing radiators to be retained in situ where possible

Radiators: To BS EN 442-1, -2 and -3. Manual radiator valves: To BS 2767.

• Material: Copper alloy.

• Finish: Satin bronze generally, chrome plated to towel warmer radiators.

Thermostatic radiator valves: To BS EN 215 and capable of providing isolation.

• Lockshield valves: To BS 2767 with matching finish.

Heating system - ancillary items Copper pipelines: To BS EN 1057, Kitemarked.

• Jointing: Integral lead-free solder ring capillary fittings to BS EN 1254-1, Kitemarked.

• Connections to appliances and equipment: Either compression fittings to BS EN 1254-2, Kitemarked, or fittings with threaded

ends to BS EN 1254-4.

• Finish:

- Pipelines for general use: Plain.

- Buried pipelines: Plastics coated.

Pipeline insulation:



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• Material: Preformed flexible closed cell or mineral fibre split tube.

• Thickness to heating and primary pipelines: Equal to the outside diameter of the pipe up to a maximum of 40 mm.

• Thickness to cold water pipelines: General internal use, 25 mm; roof space, 32 mm; external, 38 mm.

• Fire performance: Class 0 spread of flame when tested to BS 476-7.

Ventilation system Ceiling sweep fans: To BS EN 60335-2-80, and BEAB approved.

Ventilation fan units: To BS EN 60335-2-80, and BEAB approved.

Whole house ventilation fan units: To BS EN 60335-2-80, and BEAB approved.

Pull cord switches: To BS EN 61058-2-1.

3 EXECUTION

General

Concealed or inaccessible surfaces: Decorate before commencing installation.

Pipeline installation: As section 20 ‘Plumbing systems’.

Gas installation

Domestic gas pipelines: To BS 6891.

Heating system

Installation generally:

• Performance: Free from leaks and the audible effects of expansion, vibration and water hammer.

• Fixing of equipment, components and accessories: Fix securely, parallel or perpendicular to the structure of the building.

• Preparation: Immediately before installing tanks and cisterns on a floor or platform, clear the surface completely of debris and

projections.

• Corrosion resistance: In locations where moisture is present or may occur, use corrosion resistant fittings/ fixings and avoid

contact between dissimilar metals by use of suitable washers, gaskets, etc.

Feed and expansion cisterns:

• Outlet positions: Connect lowest outlets at least 30 mm above bottom of cistern.

• Access: Fix cistern with a minimum clear space of 350 mm above, or 225 mm if the cistern does not exceed 450 mm in any

dimension.

• Mounting height above the highest point of the circulation system [minimum]: 1 m.

• Insulation: Where the space below the cistern is heated, do not insulate the underside.

Ventilation systems

Passive stack ventilation systems:

• Installation: Install ductwork in runs that are as short and straight as possible, with smooth curvature to offsets.

• Arrangement: Do not install ducts at more than 45° from vertical.

• Air leakage: Prevent leakage where ducts enter rooms and around inlet grilles.

Installing ventilators for heat appliances: Do not fit with insect mesh, or any means of adjusting or restricting the opening.

Flexible ductwork:

• Installation: Fully extend without overstretching.

• Support: Form smooth flowing curves without kinking, sagging or slumping.

Rigid ductwork generally:

• Joints: Seal. Provide a robust airtight installation.

• Support: Do not distort ductwork or reduce cross-sectional area. Do not strain joints.

• Falls: Fall away from fans, dampers and other in-line accessories.

• Sleeves: Locate where ducts pass through building fabric.

Leave a gap of 10-20 mm between sleeve and duct and fill completely with mineral wool. Installing condensate drains: Provide access for

cleaning.

Site applied insulation:

• Location: Fit insulation to ductwork in unheated spaces.

• Installation: Fix securely. Leave no gaps. Make continuous.

Completion and testing

Gas installation:

• Testing, commissioning and purging gas pipelines: To BS 6891.

Heating systems:

• Testing generally:

- Notice [minimum]: 3 days.

- Preparation: Secure and clean pipework and equipment.

Fit cistern and tank covers.



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• Leak testing: Start boiler and run the system until parts are at normal operating temperatures and then allow to cool for a

period of 3 hours.

• Pressure testing: At both hot and cold conditions joints, fittings and components must be free from leaks and signs of physical

distress when tested for at least 1 hour as follows:

- Systems fed directly from the mains and systems downstream of a booster pump: Apply a test pressure equal to

1.5 times the maximum pressure to which the installation or relevant part is designed to be subjected in operation.

- Systems fed from storage: Apply a test pressure equal to the pressure produced when the storage cistern is filled to

its normal maximum operating level.

- Inaccessible or buried pipelines: Carry out hydraulic pressure test to twice the working pressure.

• Setting to work and commissioning:

- Equipment: Check and adjust operation of equipment, controls and safety devices.

- Outlets: Check operation of outlets for satisfactory rate of flow and temperature.

Natural and mechanical ventilation:

• Commissioning: Balance airflow using methods recommended by the system manufacturer.

• Operation: Examine ductwork for leakage. Test the operation of fans, equipment, controls and sensors. Verify correct

operation. Submit report.

Documentation and tools for customer:

• Operating and maintenance instructions: Submit copies of manufacturers’ operating and maintenance instructions for

equipment and controls.

• Record drawings: Submit drawings showing the location of circuits and operating controls.

• Tools: Supply tools for operation, maintenance and cleaning purposes, including keys for valves and vents.



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22 ELECTRICAL SYSTEMS

Scope: This section covers low voltage electrical installations for domestic buildings, where the electrical supply is single phase 230 V alternating current

and where the design work is to be completed by the contractor.


Design requirements General design:

• Standards: To BS 7671 and the requirements of the electricity distributor. .

Design: Complete the design and detailing of the electrical installation.

• Design information: Submit calculations, manufacturer’s literature and drawings showing equipment positions and routes.

Incoming electrical supply design:

• Capacity: Determine the anticipated maximum demand of the installation.

• Establishing the supply: Manage and liaise with the electricity distributor to establish an incoming electricity supply.

• Incoming earthing arrangement: Establish with the electricity distributor.

• Location: Coordinate the location of the incoming supply and establish the spatial requirements for the electricity distributor’s

equipment and metering.

Low voltage distribution design:

• Design: Cater for the complete working building.

• Spare capacity [minimum]. Within each consumer unit allow 10% or one spare protective device, whichever is the greater.

2 PRODUCTS

General Products generally: To BS 7671.

Consumer units: To BS EN 60439-3, ASTA certified.

Steel conduit and fittings: To BS 4568-1 and to BS EN 50086-1 and -2-1.

PVC conduit and fittings: To BS 4607-5 and to BS EN 50086-1 and -2-1.

Cables: BASEC certified.

Protective conductors: Cable conductors with yellow/ green PVC sheath.

Electrical accessories: To BS EN 60669-1. Electrical white goods: BEAB selected by client.

Final connections: Appropriately sized heat resisting white flex. Length to allow for equipment removal and maintenance.

3 EXECUTION

General General execution: To BS 7671.

• Installation: Provide a safe, well insulated, earth protected system capable of serving the building.

• Equipment: Provide electrical supplies to equipment requiring power.

• Fixed equipment: Install supplies.

• Cable and conduit routes: Position vertically or horizontally in line with equipment served, and parallel with building lines.

- Cables: Conceal wherever possible.

- Conduits: Locate where accessible.

Conduit and fittings:

• Fixing: Fix securely. Fix boxes independently of conduit.

• Jointing: Minimize number of joints. Remove burrs. Plug during building works.

• Changes of direction: Use machine-formed bends, junction boxes and proprietary components. Do not use elbows or tees.

Alternatively, use conduit boxes.

• Connections to boxes, trunking, equipment and accessories: Screwed couplings, adaptors, connectors and glands, with

rubber bushes at open ends. Provide earthing coupling/ male brass bush and protective conductor at conduit connections to

boxes and items of equipment, other than those with threaded entries.

Cable routes: Position cables 150 mm [minimum) from other services running parallel. Place cables below heating pipes where running

parallel.



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Power accessories and equipment

Location: Coordinate with other wall or ceiling mounted equipment.

Positioning: Place accurately and square to vertical and horizontal axes.

Lighting accessories and equipment

Installing luminaires:

• Supports: Adequate for weight of luminaire.

• Locations: Coordinate with other wall or ceiling mounted equipment.

Completion Final fix of accessory faceplates, luminaires and other equipment: After completion of building painting.

Cleaning:

• Electrical equipment and equipment not supplied but installed under the electrical works: Clean immediately before handover.

Inspection and testing:

• Standard: To BS7671.

• Notice before commencing tests [minimum): 24 hours.

Labels and signs: Fix securely before system is tested. Documentation for customer:

• Contents:

- Full technical description of installed systems.

- Manufacturers’ operating and maintenance instructions for fittings and apparatus.

- Manufacturers’ guarantees and warranties.

- As-installed drawings showing circuits and their ratings and locations of fittings and apparatus.

- List of normal consumable items.

- Inspection and completion certificates.

• Timing: Submit at completion.



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23 COMMUNICATIONS AND SECURITY SYSTEMS

Scope:

This section covers television distribution systems, fire detection and alarm systems, access control systems and intruder detection and alarm systems,

and where the design work is to be completed by the contractor.

Related work:

• Domestic electrical work - see section 22 'Electrical systems'.


Design requirements Design: Complete the design and detailing of the communications and security systems.

Design information: Submit drawings showing equipment positions and routes, with calculations.

2 PRODUCTS

Television distribution system Antennae: To BS 5640-1, -2 and in accordance with BS 6330.

Cables: In accordance with BS 6330.

Outlets: To BS 5733, Kitemarked, and to BS EN 60669-1.

Finish: Match electrical accessories.

Fire detection and alarm system

Smoke alarms: To BS 5446-1, Kitemarked. Carbon monoxide alarms: To BS EN 50291.

3 EXECUTION

General Installing cables generally: To BS 7671.

• Cable and conduit routes: Position vertically or horizontally in line with equipment served, and parallel with building lines.

• Cables: Install neatly and securely. Conceal wherever possible.

• Conduits: Locate where accessible.

• Distance from other services running parallel [minimum]: 150 mm. Place cables below heating pipes.

• Jointing: At equipment and terminal fittings only.

• Length of final connection: Sufficient for equipment removal and maintenance.

Accessories and equipment:

• Location: Coordinate with other wall or ceiling mounted equipment.

• Positioning: Accurate and square to vertical and horizontal axes.

Television distribution system Installing television antennae, cabling and outlets: In accordance with BS 6330.

• External wall entry: Slope downwards towards external wall, form drip loop or provide proprietary rain cover.

Fire detection and alarm system

System: In accordance with BS 5839-6.

• Power supply: Dedicated circuit from the buildings main switchboard or consumer unit.

Completion Testing:

• Television distribution system: To BS EN 50083-7 and in accordance with BS 6330.

• Fire detection and alarm system: In accordance with BS 5839-6.

- Certification: To BS 5839-6, Annex C.

• Access control system: To BS EN 50133-1.

- Intruder detection system: To BS EN 50131-1. Documentation for customer:

• Content:

- Full technical description of each system installed.



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- Manufacturers’ operating and maintenance instructions for fittings and apparatus.

- Manufacturers’ guarantees and warranties.

- As-installed drawings showing circuits and their ratings and locations of fittings and apparatus. –

- List of normal consumable items.

- Inspection and completion certificates.

• Timing: Submit at completion.

specification

Documents