specification for road works series 2400 - brickwork ... · 24/1 are for lime putty conforming to...

Specification for Road Works Series 2400 - Brickwork, Blockwork and Stonework

CC-SPW-02400

December 2013

Standards Construction & Commissioning

CC

TRANSPORT INFRASTRUCTURE IRELAND (TII) PUBLICATIONS

About TII Transport Infrastructure Ireland (TII) is responsible for managing and improving the country’s national road and light rail networks. About TII Publications TII maintains an online suite of technical publications, which is managed through the TII Publications website. The contents of TII Publications is clearly split into ‘Standards’ and ‘Technical’ documentation. All documentation for implementation on TII schemes is collectively referred to as TII Publications (Standards), and all other documentation within the system is collectively referred to as TII Publications (Technical). This system replaces the NRA Design Manual for Roads and Bridges (NRA DMRB) and the NRA Manual of Contract Documents for Road Works (NRA MCDRW). Document Attributes Each document within TII Publications has a range of attributes associated with it, which allows for efficient access and retrieval of the document from the website. These attributes are also contained on the inside cover of each current document, for reference. For migration of documents from the NRA and RPA to the new system, each current document was assigned with new outer front and rear covers. Apart from the covers, and inside cover pages, the documents contain the same information as previously within the NRA or RPA systems, including historical references such as those contained within NRA DMRB and NRA MCDRW. Document Attributes

TII Publication Title Specification for Road Works Series 2400 - Brickwork, Blockwork and Stonework

TII Publication Number

CC-SPW-02400

Activity Construction &

Commissioning (CC)

Document Set

Standards

Stream Specification for Works (SPW)

Publication Date December 2013

Document Number

02400 Historical Reference

Series 2400

NRA DMRB and MCDRW References For all documents that existed within the NRA DMRB or the NRA MCDRW prior to the launch of TII Publications, the NRA document reference used previously is listed above under ‘historical reference’. The TII Publication Number also shown above now supersedes this historical reference. All historical references within this document are deemed to be replaced by the TII Publication Number. For the equivalent TII Publication Number for all other historical references contained within this document, please refer to the TII Publications website.

Volume 1 Series 2400

NRA Specification for Road Works Brickwork, Blockwork and Stonework

December 2013 1

BRICKWORK, BLOCKWORK AND

STONEWORK

Contents

Clause Title Page

2400 Introduction ............................................................................................................................... 3

2401 Cement ...................................................................................................................................... 3

2402 Aggregates ................................................................................................................................ 3

2403 Water ......................................................................................................................................... 3

2404 Mortar ....................................................................................................................................... 3

2405 Lime Mortar .............................................................................................................................. 4

2406 Masonry Units (Bricks) ............................................................................................................ 4

2407 Blocks ....................................................................................................................................... 4

2408 Manufactured Stone .................................................................................................................. 5

2409 Natural Stone ............................................................................................................................ 5

2410 Reinforcement ........................................................................................................................... 5

2411 Anchorages, Dowels, Fixings and Ties..................................................................................... 5

2412 Brickwork and Blockwork ........................................................................................................ 5

2413 Stonework ................................................................................................................................. 6

2414 Cold Weather Working ............................................................................................................. 7

2415 Protection of New Work ........................................................................................................... 7

2416 Brick, Block and Stone Facework Fixed to Concrete ............................................................... 7

2450 Masonry Repointing of Historic Structures - Introduction ....................................................... 8

2451 Masonry Repointing of Historic Structures - Mortar - Constituent Materials .......................... 8

2452 Masonry Repointing of Historic Structures – Mortar ............................................................. 10

2453 Masonry Repointing of Historic Structures - Proprietary Pre-Bagged Mortars ..................... 11

2454 Masonry Repointing of Historic Structures - Preparation ...................................................... 11

2455 Masonry Repointing of Historic Structures - Application Methods ....................................... 12

2456 Masonry Repointing of Historic Structures - Finishing .......................................................... 12

2457 Masonry Repointing of Historic Structures - Equipment ....................................................... 13



December 2013 2

2458 Masonry Repointing of Historic Structures - Special Structures ............................................ 13

2459 Masonry Repointing of Historic Structures - Cold Weather Working ................................... 13

2460 Masonry Repointing of Historic Structures - Protection of New Work ................................. 13

2461 Masonry Repointing of Historic Structures - Protection of the Environment ........................ 14

2462 Masonry Repointing of Historic Structures - Health & Safety ............................................... 14

2463 Masonry Repointing of Historic Structures - Surface Finish .................................................. 14

2464 Masonry Repointing of Historic Structures - Materials - Compliance ................................... 14

2465 Masonry Repointing of Historic Structures - Workmanship - Compliance ............................ 16



December 2013 3

Brickwork, Blockwork and Stonework

2400 Introduction

1 Clauses 2401 to 2416 shall be used for brickwork, blockwork and stonework within new

construction. Clauses 2450 to 2465 shall be used for masonry repointing and reconstructing of

historic structures where a lime mortar shall be used.

Any structure which was constructed using lime mortar is considered to be a historic structure.

2401 Cement

1 Cement shall be one of the following:

i) Portland cement (CEM 1) conforming to IS EN 197-1;

ii) Masonry cement conforming to IS EN 413-1;

iii) Sulfate-resisting Portland cement conforming to IS EN 197-1 where described in

Appendix 24/1.

2402 Aggregates

1 Fine aggregate (sand) shall conform to IS EN 13139.

2403 Water

2 If water for the Works is not available from a public piped water supply, the water shall comply

with the guidance given in IS EN 1008. The sulphate content of the water shall be tested in

accordance with IS EN 1744-1 and shall not exceed 1.4g of sulphate (SO4) per litre. Water from

the sea or tidal rivers shall not be used.

2404 Mortar

1 Cement mortar for brickwork, blockwork and stonework shall be mixed in the proportions given

in Table 24/1 according to the mortar designation described in Appendix 24/1.

2 The chloride ion content of the mortar determined in accordance with IS EN 1744-1 shall not

exceed 0.3% of the mass of cement for mortar made with Portland cement and 0.2% for mortar

made with sulfate-resisting Portland cement. Calcium chloride or admixtures containing calcium

chloride shall not be used.

3 For work in which cement mortars of designation (ii) or (iii) as identified in Appendix 24/1 are

required, the appropriate mortar mix proportions shall be selected from Table 24/1. If the work is

carried out in frosty weather and the bricks are wet when laid, then a cement sand mortar with an

air entraining plasticiser shall be used. Admixtures shall conform to IS EN 934-3 and any

additional performance requirements stated in Appendix 24/1, and shall not contain calcium

chloride. When additives or admixtures are used, the recommendations of the admixture

manufacturer shall be followed.



December 2013 4

Table 24/1: Mortar Proportions by Volume

Mortar

designation

Cement: lime:

sand

Masonry

cement: sand

Cement:

sand with

plasticiser

(i) 1:0 to ¼:3 - -

(ii) 1: ½:4 to 4½ 1:2½ to 3½ 1:3 to 4

(iii) 1:1:5 to 6 1:4½ 1:5 to 6

4 The inclusion of lime in mortar designation (i) is optional. The proportions of lime given in Table

24/1 are for lime putty conforming to IS EN 459-1. If the lime is measured as the dry hydrate, the

amount may be increased up to 1.5 volumes for each volume of lime putty. Where a range of sand

contents is given in the Table, the higher shall be used for sand that is well graded and the lower

for coarse or uniformly fine sand.

5 Mortar shall be mixed thoroughly either by hand or mechanically until its colour and consistency

are uniform. The constituent materials shall be accurately gauged, allowance being made for

bulking of sand. Mortar shall be made in small quantities only as and when required. Mortar

which has begun to set or which has been mixed for a period of more than 1 hour in the case of a

mortar designation (i) or more than 2 hours in the case of other designations shall be discarded. If

ready mixed mortars are used, their use shall be in accordance with the manufacturer’s

instructions and IS EN 998-1 and IS EN 998-2.

2405 Lime Mortar

1 Lime mortar shall comply with clauses 2450 to 2465 of this document,

2406 Masonry Units (Bricks)

1 Clay masonry units (bricks) shall conform to the particular requirements of IS EN 771-1

described in Appendix 24/1.

2 Calcium silicate masonry units (bricks) shall conform to IS EN 771-2.

3 Aggregate Concrete masonry units (bricks) shall conform to IS EN 771-3.

4 Bricks beneath frames for chambers and gullies, and for the construction of brick chambers, shall

be High Density clay masonry units conforming to IS EN 771-1. The mean compressive strength

of the bricks shall be not less than 75 N/mm2 when tested in accordance with IS EN 772-1. The

water absorption of the bricks shall be not more than 7% by mass when tested in accordance with

IS EN 772-7.

5 Bricks to be used for facework shall be of freeze/thaw resistance category F2 and active soluble

salts content category S2.

2407 Blocks

1 Aggregate concrete masonry units (blocks) shall comply with the particular requirements of IS

EN 771-3 described in Appendix 24/1.



December 2013 5

2408 Manufactured Stone

1 Manufactured stone shall be used only in blockwork and shall comply with IS EN 771-5 and any

particular requirements described in Appendix 24/1.

2409 Natural Stone

1 Unless otherwise required in Appendix 24/1, Building stone shall comply with IS EN 771-6 and

be of the type and quality described in Appendix 24/1.

2410 Reinforcement

1 Wire or fabric, laid between brickwork or blockwork shall be austenitic stainless steel to IS EN

10088-1, designation 1.4301, 1.4401 or 1.4436, softened condition, excluding free machining

specifications.

2 Steel bars laid between brickwork or blockwork shall be made from austenitic stainless steel

designation 1.4301 or 1.4436 and Grade 200 or 500 steel bars complying with BS 6744, softened

condition, excluding free machining specifications.

Table 24/2: Austenitic Stainless Steel

Form Standard to be complied with

Strip IS EN 10029, IS EN 10048, IS EN

10051, IS EN ISO 9445

Rod IS EN 10088-1

Bar BS 6744

Tube IS EN 10296-2

Wire IS EN 10088-3

2411 Anchorages, Dowels, Fixings and Ties

1 Anchorages, dowels, fixings and ties shall be austenitic stainless steel designation 1.4301, 1.4401

or 1.4436, softened condition, complying with the requirements given in the Standards listed in

Table 24/2.

2412 Brickwork and Blockwork

1 Brickwork and blockwork shall comply with this Clause and the NRA Road Construction Details

listed in Appendix 24/2. Brickwork and blockwork shall be laid on a full bed of mortar and

bonded as described in Appendix 24/1. Single frogged bricks shall be laid with the frog

uppermost. Perpends between bricks and blocks shall be filled with mortar before the next mortar

bed is laid. Whole bricks and blocks shall be used except where it is necessary to cut closers.

2 Brickwork and blockwork shall be built uniformly. Corners and other advanced work shall be

stepped back and not raised above the general level more than 900 mm. Courses shall be kept

horizontal and matching perpends shall be in vertical alignment.

3 Unless otherwise stated in App 24/1, overhand work shall not be permitted.



December 2013 6

4 Reinforcement in brickwork and blockwork shall be completely embedded in the mortar joint.

5 Where pointing is required in Appendix 24/1 the joint shall be raked out to a depth of 12 mm and

after the completion of the entire facework, pointed in mortar as described in Appendix 24/1.

6 Where jointing is required in Appendix 24/1 it shall be done as the work proceeds to the finish

described in Appendix 24/1.

Storage

7 Bricks shall be unloaded with due care to minimize damage, placed on site in different stacks

according to strength and type, and be marked clearly. They shall be stacked on prepared level

areas, avoiding ground contamination and be protected from rain or snow to prevent saturation of

the bricks.

2413 Stonework

General

1 Stonework shall comply with this Clause and the NRA Road Construction Details listed in

Appendix 24/2. Except where otherwise described in Appendix 24/1 or on the drawings in the

Contract, the length of any stone shall not exceed three times its height. The breadth on the bed

shall be not less than 150 mm, nor greater than three-quarters of the thickness of the wall.

2 All stratified stone possessing bedding planes shall be laid with its natural bed as nearly as

possible at right angles to the direction of load. In the case of arch rings, the natural bed shall be

radial.

3 Facework quoins shall be built to a height not exceeding 900 mm in advance of the main body of

the work and adjacent walling stepped down on either side.

4 Stone facework between the quoins shall then be built to a height not exceeding 450mm above

the backing which shall then be brought up level with the completed facework. At no time shall

the backing be built up higher than the facework.

5 Except for dry rubble walling, all joints shall be sufficiently thick to prevent stone-to-stone

contact and shall be completely filled with mortar.

Ashlar

6 All stones shall be dressed to accurate planes on the beds and joints, and they shall be fair and

neatly or fine tooled on the face as described in Appendix 24/1.

Block-in-course

7 Beds and joints shall be squared and dressed for a distance of at least 225 mm from the exposed

face. Bond stones shall form not less than one sixth of the area of the exposed face and shall

extend at least 900 mm into the wall or for the full thickness of the wall if the latter is less than

900mm. Unless described in Appendix 24/1 as tooled or worked, the exposed face of all stone

shall be blocked and left rough. Arrises shall be dressed square at all beds and joints.



December 2013 7

Squared Random Rubble Coursed and Uncoursed

8 All stones shall be truly squared and dressed on the beds and joints for a distance of at least 125

mm from the exposed face. Bond stones shall be provided at the rate of not less than one to every

square metre of exposed face, and shall measure not less than 150 mm x 150 mm on the face, and

not less than 450 mm or the full thickness of the wall if the latter is less than 450 mm. Sneck

stones shall be not less than 75 mm in any dimension. Vertical joints shall not include more than

three consecutive stones, and the horizontal lapping of the stones shall be not less than 100 mm.

Random Rubble Coursed and Uncoursed

9 All stones shall be carefully set with a bond stone provided at the rate of not less than one to

every square metre of exposed face. Bond stones shall measure not less than 150 mm x 150 mm

on the exposed face, and not less than 450 mm in length or the full thickness of the wall if the

latter is less than 450 mm unless otherwise described in Appendix 24/1. For coursed work the

joints shall be levelled as described in Appendix 24/1 and the backing flushed up in mortar.

Dry Rubble

10 Dry rubble stonework shall be constructed generally to the requirements of uncoursed random

rubble stonework, as specified in sub-Clause 9 of this Clause but without mortar. All stones shall

be carefully shaped to obtain a close fit at all beds and joints, any interstices between the stones

being filled with selected stone chippings or spalls. The exposed tops or copings of dry rubble

walls shall be formed as shown on the drawings in the Contract.

Special Stonework Including Quoins, Copings, Plinths, Voussoirs etc.

11 Special stonework shall consist of selected and approved stones dressed to the shapes and

dimensions, and where required their faces worked, all as shown on the drawings in the Contract.

2414 Cold Weather Working

1 No bricks, blocks or stones shall be laid and mortar shall not be mixed when the air temperature is

below 1°C measured on a rising thermometer or below 3 °C measured on a falling thermometer.

All materials when used shall be free from snow, ice and frost. Mortar is not to be laid on frozen

surfaces. Wet bricks or blocks shall not be used when there is a danger of freezing.

2415 Protection of New Work

1 Immediately after laying and for 3 days thereafter, brickwork, blockwork and stonework shall be

protected against the harmful effects of weather. The upper surface of newly laid brickwork,

blockwork and stonework shall be protected against rain as the work proceeds until such time as

the work is completed and the upper damp-course, coping or other finishing feature is laid.

2 All visible brickwork, blockwork and stonework and any surface below such work which is

visible at the completion of the Works shall be clean and free from damage and spillage. All

purpose-made open joints shall be free from debris of any description.

2416 Brick, Block and Stone Facework Fixed to Concrete

1 Any loose material shall be removed from the concrete, and its surface washed with clean water

before any bricks, blocks or masonry is laid.



December 2013 8

2 The portion of the stainless steel fixing projecting from the concrete shall be completely

embedded in the mortar of the facework and shall be kept back a minimum of 30 mm from the

face of the brickwork and blockwork or 40 mm from the face of the masonry.

3 The cavity between brick and block facework and the concrete shall be completely filled as the

work proceeds with mortar of the same mix as that specified for the facework.

4 The variation in depth, front to back of stones for natural stone facework shall not exceed that

described in Appendix 24/1 and the space between the facework and the backing shall be

completely filled as the work proceeds with concrete strength class C12/15 and maximum

nominal upper aggregate size (Dmax) of 10mm complying with Series 1700.

2450 Masonry Repointing of Historic Structures - Introduction

1 A lime mortar shall be used for repointing masonry and reconstruction of historic structures. All

lime mortar works shall be carried out in compliance with Clauses 2450 to 2465.

2451 Masonry Repointing of Historic Structures - Mortar - Constituent Materials

Cement

1 Cement, if required by Table 24/4 shall comply with Clause 2401 of this document.

Lime

2 Lime shall be Natural Hydraulic Lime (NHL) in compliance with IS EN 459-1.

3 Lime putty shall be between 3-12 months matured and have a minimum relative bulk density of

1350kg/m3.

Aggregates

4 Fine aggregate (sand) shall conform to IS EN 13139 and shall have a maximum particle size of

greater than or equal to 1.5mm and less than or equal to 5mm with no more than 3% passing

0.075mm (wet screened).

5 The aggregate shall be well graded with the grading curve displaying a good distribution between

the various sizes within the tolerances as detailed in Table 24/3.



December 2013 9

Table 24/3: Aggregate Grading Requirements

ISO 565 sieve size Percentage by mass

passing ISO sieves

mm

5 98-100

2.36 90-100

1.18 70-100

m

600 40-100

300 5-70

150 0-15

75 0-3a

a0-7% for crushed stone sands

6 The maximum particle size shall not exceed one half of the joint width.

7 Care should be taken to ensure that aggregate is neither too dry nor too wet so the effect of

bulking with wetting is limited. Aggregate for spraying using a dry-mix process shall be supplied

dry or shall be dried such as to permit satisfactory blending prior to pumping.

8 The aggregate grading requirements in this clause are not appropriate for ashlar stonework where

the joint size is less than 10mm.

Water

9 Water shall comply with Clause 2403 of this document.

Additives

10 Where pozzolan is required it shall be as described in Appendix 24/3 and shall be between 3-6%

pozzolan.

11 Pozzolans shall be calcined refined china clay or other as specified in Appendix 24/3 and shall be

measured by volume accurately.

12 Where used, air entrainer shall not produce an air content in the mortar that will exceed 10-12%

of air unless specified in Appendix 24/3.

Storage

13 Lime shall be kept in a dry store and once opened should generally be used on the same day. Part-

used bags can be kept for a maximum of one day provided the bag top is folded over and the bag

placed into dry store.

14 Aggregates shall be covered to prevent ingress of precipitation and to stabilise water content.



December 2013 10

2452 Masonry Repointing of Historic Structures – Mortar

1 Limes from different manufacturers can have different relative bulk densities (RBD) leading to a

requirement to vary mix proportions in relation to the RBD of the specific lime used. The

guidance provided in NG 2452 shall be taken into account during the design of a proposed mortar

mix; the effectiveness of which will be determined via conformancy testing.

2 For general use, lime mortar mixes for brickwork, blockwork and stonework shall be selected

taking into account the relative strength of the masonry being repointed, the mortar class and

environment in accordance with the guidelines contained in Table 24/4.

3 Cement-based mortars are not suitable for use in arch barrels and should only be used where the

Employer’s Representative considers that its use is justified on strength grounds or where no

movement or flexibility in the stonework is anticipated.

4 The chloride ion content of the mortar determined in accordance with IS EN 1744-1 shall not

exceed 0.3% of the mass of cement for mortar made with Portland cement and 0.2% for mortar

made with sulphate-resisting Portland cement. Calcium chloride or admixtures containing

calcium chloride shall not be used.

5 Mortar shall be mixed thoroughly either by hand or mechanically using a paddle mixer until its

colour and consistency are uniform. The constituent materials shall be accurately gauged,

allowance being made for bulking of sand. Mortar shall be made in small quantities only as and

when required.

6 Cementitious mortar which has begun to set or which has been mixed for a period of more than 1

hour in the case of a (Table 24/4) mortar reference (d) or more than 2 hours in the case of mortar

reference (e) shall be discarded.

7 Mortars for hand application should be mixed with the minimum amount of water to create a stiff

mortar to reduce shrinkage and aid compression during application.

8 In situations where joints below water are to be repointed, the area immediately adjacent to the

wall shall be adequately bunded and pumped clear such that repointing can be carried out in dry

conditions. The new mortar shall be protected from water until adequately cured, minimum 72

hours, or as directed by the Employer’s Representative.

9 In areas where it is impractical to bund adjacent to walls due to depth/flow of water proprietary

fast-set, chemically inert, cementitious materials that can be placed under water may be used to

repoint masonry only if approved by the Employer’s Representative.

10 When replacing missing arch barrel stones in overhead locations propping is used where possible

to keep the stone in place until the mortar has cured. On occasion, due to access restrictions,

propping of replacement arch barrel stones may not be possible. In such instances use of fishing

twine cast into voids prior to insertion of replacement arch barrel stones, and subsequently tied

around the stone may be necessary to keep the replacement stone in place until the mortar has

cured. Alternatively, with the approval of the Employer’s Representative stainless steel tying wire

may be used. Use of non-stainless steel tying wire is not permitted.



December 2013 11

11 Where use of any method to provide temporary support is impractical, a gauged mortar

comprising 1 part lime putty, 1 part NHL5 and 6 parts aggregate (reference (c) in accordance with

Table 24/4) can be used. This provides a mortar with a very 'sticky' consistency, which is often

able to support pinning stones of considerable weight without additional propping. Gauged

mortars are difficult to mix and should only be used where other methods are not practical and

where prior consent has been obtained from the Employer’s Representative.

2453 Masonry Repointing of Historic Structures - Proprietary Pre-Bagged Mortars

1 Proprietary pre-bagged mortars that satisfy the strength and other requirements of the Contract

may be used, subject to approval by the Employer’s Representative. As a minimum requirement,

the mortars shall meet the requirements of the designated mortar type as illustrated in Table 24/4.

2 Pre-bagged mortars to be used in accordance with manufacturer’s instructions at all times.

2454 Masonry Repointing of Historic Structures - Preparation

1 Areas to be repointed shall be cleaned of all vegetation and algae. Invasive roots shall be removed

in so far as possible. Those not able to be fully removed shall be removed or cut back as far as

possible and treated with a suitable systemic herbicide, as approved by the Employer’s

Representative, such as to prevent regrowth. The extent of cut back in lieu of full removal shall be

agreed with the Employer’s Representative.

2 All loose mortar, soil, deleterious material etc., shall be removed from the joint and the joint

cleaned prior to repointing.

3 In structures subject to significant water ingress from the backfill no repointing works shall be

undertaken until measures have been taken to prevent further water ingress.

4 Areas to be repointed shall either be marked on the Drawings or shall be clearly defined on site

by the Employer’s Representative chalk markings identifying the extent of the Works.

5 Unless otherwise directed by the Employer’s Representative, prior to commencement of

repointing works, all loose mortar shall be removed over an area not exceeding 2 square metres at

any one time to a depth of 50mm. This area shall not be greater than 3m measured along the line

of the joints in compression or greater than 1/3rd

of the full width of the structure. In addition,

where any sound mortar is found within a depth of 50mm this too shall be removed in order to

ensure a sufficient bond. Care shall be taken not to damage stone masonry during the raking out

process.

6 Angle grinders or other disc cutting machinery should not be used to remove existing mortar from

the joints. If for reasons such as removal of existing destructive hard sand and cement mortar it is

deemed necessary to use such machines then approval from the Employer’s Representative shall

be sought prior to such works commencing. It must be demonstrated that their use will not widen,

straighten, or skew existing joints or make overruns into neighbouring stones.

7 Remaining joint material shall be brushed clean and washed with water. Absorbent masonry

should be damp at time of application of the fresh mortar. Impervious masonry should be dry

when the work commences wherever practical.



December 2013 12

2455 Masonry Repointing of Historic Structures - Application Methods

1 Method of application shall be approved by the Employer’s Representative, and shall comprise

either:

i) Hand application;

Using flat steel jointing tools of varying width to suit individual joints (pointing

trowels should not be used for mortar insertion).

ii) Spray Application:

Using dry-mix process equipment the nozzle of which shall be capable of allowing

full and continuous control of the quantity of water to be added as well as ensuring

effective mixing of sprayed mortar ingredients.

2 Equipment shall be set up in accordance with the manufacturer's recommendations and be

designed so that dust is kept at the lowest possible level.

3 Unless otherwise directed by the Employer’s Representative, joints up to 50mm in depth shall be

repointed by hand, tamped with a stiff brush or lightly scraped

4 Unless otherwise directed by the Employer’s Representative, joints in excess of 50mm deep shall

be sprayed in layers of appropriate thickness to prevent slumping, which is dependent on joint

width and aggregate type. No voids shall be created between individual layers.

5 Spraying shall be terminated at the face of the masonry being repointed. The finished level shall

be hand-finished (tamped and scraped after 12-24 hours depending on weather conditions).

6 Suitably sized pinning stones shall be used to limit the joint width to a maximum of 20mm for the

full depth of the joint.

7 Overhead pinning stones shall be supported in position by props or other means, as approved by

the Employer’s Representative as necessary until surrounding mortar has adequately cured.

8 Overspill/splashback of sprayed mortar shall be cleaned from the face of the masonry

immediately to prevent defacing of the appearance of the bridge.

2456 Masonry Repointing of Historic Structures - Finishing

1 Joints shall be ‘fully filled’ flush with the surrounding masonry or to the weathered edge unless

otherwise directed by the Employer’s Representative. Once the surface of the mortar is firm

(usually the day after application) the surface should be tamped with a stiff brush or lightly

scraped to expose the aggregate to improve the appearance of the mortar.

2 Any overspill/splashback remaining on the face of the stone shall be cleaned to remove all traces

of excess mortar.



December 2013 13

2457 Masonry Repointing of Historic Structures - Equipment

1 All equipment used for batching and mixing of materials and the application of all types of mortar

shall be of designs approved by the Employer’s Representative and shall be maintained in proper

working order for the duration of the works. Where appropriate, calibration of machinery shall be

certified.

2 Full details of equipment to be used shall be provided to the Employer’s Representative prior to

the commencement of the Works. The mortar spraying machine and ancillary equipment shall be

of an adequate capacity for the volumes to be applied. Equipment shall be leak-proof with respect

to all materials.

3 Equipment operators shall be experienced in the use of the machinery being used.

4 Spraying equipment shall be capable of feeding materials at a regular rate and ejecting mortar

from the nozzle at velocities that will allow adherence of the mortar to the joints with a minimum

of rebound and maximum adhesion and density.

5 Equipment shall be thoroughly cleaned at least once per shift, or at other appropriate intervals if

hydration control mixtures are used, to prevent accumulations of deposits.

6 Transport pipes consisting of hoses or pipes shall be laid straight or in gentle curves. They shall

have a uniform diameter appropriate to the mix characteristics and shall be free of any dents or

kinks.

7 Working areas shall be well illuminated to the approval of the Employer’s Representative. Cap

lamps attached to safety helmets are not acceptable as sufficient illumination.

2458 Masonry Repointing of Historic Structures - Special Structures

1 Listed structures and structures of special historical or architectural interest shall be treated with

additional care and attention.

2 Specialist advice should be sought from The Department of Arts, Heritage and the Gaeltacht or its

successors and other interested parties when dealing with such structures.

3 Any special requirements in respect of such structures shall be clearly stated in Appendix 24/3.

2459 Masonry Repointing of Historic Structures - Cold Weather Working

1 No repointing shall take place when the air temperature in the shade is below 5°C.

2460 Masonry Repointing of Historic Structures - Protection of New Work

1 Immediately after repointing and for a minimum of 3-4 days thereafter; and longer if conditions

dictate, the Works shall be protected against the harmful effects of weather (wind, sun, rain and

frost) some of which can lead to harmful accelerated curing. New mortar must be kept in a damp,

(not wet) condition for at least 72 hours after placing, this should be taken into account, especially

at weekends and during holiday periods. These arrangements for the ongoing protection of the

Works shall be to the satisfaction of the Employer’s Representative.



December 2013 14

2 Where there is any potential for frost or freezing this may include the provision of insulating

blankets. The upper surface of newly repointed brickwork, blockwork and stonework shall be

protected against wind, sun, rain and frost as the work proceeds until such time as the work is

completed and the upper coping or other finishing feature is laid and cured adequately - for a

minimum of 3 days.

2 All visible brickwork, blockwork and stonework and any surface below such work which is

visible at the completion of the Works shall be clean and free from damage and spillage.

2461 Masonry Repointing of Historic Structures - Protection of the Environment

1 Due care and attention shall be paid to the containment of removed pointing material and

protection of the watercourse during the repointing process. Adequate precautions shall be taken

to ensure that no waste material enters the watercourse or pollutes the land. Run-off containing

pollutants into the surrounding soil will not be permitted

2 Waste materials shall be disposed of off-site in accordance with all applicable legislation.

3 Due care shall be paid to wildlife in the vicinity of the Works. Special attention shall be paid in

respect of the presence of bats, which are a protected species, and which are often found to roost

in voids in masonry arch bridges.

2462 Masonry Repointing of Historic Structures - Health & Safety

1 Application of repointing materials and all preparatory works shall meet the requirements of the

Safety, Health & Welfare at Work (Construction) Regulations and all other applicable legislation

which might supersede the above.

2463 Masonry Repointing of Historic Structures - Surface Finish

Trial Panels

1 Sample panels of minimum 2m x 1m in size shall be prepared at each site and for each mix to be

used for the approval of the Employer’s Representative. Separate panels shall be prepared for

each method of application (e.g. spraying and hand pointing).

2 The location of sample panels shall be agreed with the Employer’s Representative. Sample panels

should be prepared in such a place and location that after acceptance, they may be retained as part

of the completed works, but in all events will be the exemplar panel for reference purposes.

Control of Colour

3 Each constituent material shall be obtained from a single consistent source. The aggregates shall

be free of any impurities that may cause staining. The mix proportions and the grading shall be

consistently maintained.

2464 Masonry Repointing of Historic Structures - Materials - Compliance

Aggregate

1 Results of aggregate grade-tests shall be provided to the Employer’s Representative prior to the

commencement of the Works. Further samples shall be grade-tested at the rate of 1no per week.



December 2013 15

Mortar

2 Sampling and testing of mortar, to include compressive and flexural strength tests, shall be

undertaken in accordance with IS EN 459-2 unless otherwise described in Appendix 24/3.

Strength

3 General. Compliance with the specified characteristic strength detailed in Table 24/4 shall be

based on tests made on prisms at the age of 28 and 91 days.

4 Unless otherwise instructed by the Employer’s Representative the rate of sampling per bridge

shall be as given in Table 24/5; but not less than one sample per week shall be taken of each

mortar mix used.

5 Sampling and testing. The procedure for sampling, testing and compliance given in IS EN 196-1

as amended by IS EN 459-2 shall be used.

6 Any variation in compressive strength greater than 35% of the specified 28-day value or 20% of

the 91-day value will result in the mortar being declared non-conforming.

Table 24/5:Minimum rates of sampling and testing

Type of mortar 1no 3-gang mould per:

Hand applied mix week per bridge per mix

Spray applied mix week per bridge per mix

Gauged mix week per bridge per mix

Pinning Stones

7 The material for pinning stones should be such that it can be easily shaped and shall have a rough

surface to aid adhesion. Samples of pinning stones shall be provided for approval to the

Employer’s Representative a minimum of 7-days prior to start of the Works. Stones which are

considered too hard to permit shaping, or too soft, will not be accepted.

Records

8 Records of all orders, deliveries of materials and tests undertaken shall be maintained and

provided to the Employer’s Representative. Results of tests shall be provided no later than 7-days

following the physical test procedure.

9 Daily Temperature measurements (maximum/minimum) during the months of October-April and

at other times as directed by the Employer’s Representative shall be provided to the Employer’s

Representative.

Trial Mixes

10 When required by Appendix 24/3 trial mixes shall be undertaken for acceptability prior to

commencement of the Works.

11 Where trial mixes have been specified, the mixes shall be produced using the same gauges as will

be used on site. The mass of each ingredient shall be recorded together with the moisture content

of the aggregate used.



December 2013 16

12 The mortar shall be prepared using the mixer type which is to be used on site and shall be tested

for compressive and flexural strength at 28 and 91 days or as otherwise directed by the

Employer’s Representative.

13 Where trial mixes have been specified, assessment of site mortars for conformity with the

specification will entail comparison of site test results with the trial mortar test results.

14 Any variation in compressive strength greater than 35% of the specified 28-day value or 20% of

the 91-day value will be considered significant and will result in the mortar being declared non-

conforming.

Procedures in the event of non-conformancy of materials

15 In the event of non-conformancy of materials to specification, all non-conforming mortar shall be

removed in a manner which does not result in either damage to the stone masonry or potential

instability of the structure non-conforming mortar shall be replaced with compliant material.

2465 Masonry Repointing of Historic Structures - Workmanship - Compliance

Site Investigation

1 Satisfactory placement of sprayed or hand applied mortars will be confirmed by one, or all, of the

following methods as instructed by the Employer’s Representative:

i) 18mm diameter holes drilled full depth into the joint followed by visual inspection via

endoscopic survey;

ii) Localised breakouts of newly placed mortar.

2 Holes and localised breakouts shall subsequently be reinstated to the satisfaction of the

Employer’s Representative.

Procedures in the event of non-conformancy of workmanship

3 In the event of non-conformancy of workmanship to specification, all non-conforming mortar

shall be removed in a manner which does not result in either damage to the stone masonry or

potential instability of the structure and replace the non-conforming mortar with compliant

material.



December 2013 17

Table 24/4 - Mortar Use Guide General use hand pointing and mechanical pointing mortar work

Masonry Type Parapet & Copings

Spandrel Walls Abutments & Soffit to Arch Barrel

Above flood

level

Below flood

level

Above flood

level

Below flood

level

Mortar Classa (Environment)

Dense impermeable masonry. Squared or

random. Brick, Basalt, Granite etc. (No Suction)

9 – 10

(severe)

5 - 6

(moderate)

9 - 10

(severe)

5 - 6

(moderate)

9 - 10

(severe)

Medium permeability masonry. Squared or

random. Brick, Sandstone, Limestone and mixed

quality field stone masonry. (Moderate Suction)

9 - 10

(severe)

5 - 6

(moderate)

9 - 10

(severe)

5 - 6

(moderate)

9 - 10

(severe)

High permeability masonry. Squared or random.

Brick, Sandstone, Limestone and poor quality

mixed field stone masonry. (High Suction)

9 - 10

(severe)

5 - 6

(moderate)

9 - 10

(severe)

5 - 6

(moderate)

9 - 10

(severe)

Mix

R

e

f

:

Mix Ratio

By

Volume

Lime:Sand

(+ %

additive)

Lime

Binder

Resistance

to Freeze

Thaw (90

days)

Resistance to

Sulfate

Exposure (90

days)

Resistance to

Freeze Thaw in

Sulfate

Conditions (90

days)

Carbonation

Rate

Capillary

Rise (mm

rise @ 6

hours)

Typical Expected

Compressive

Strength

Typical

Expected

Flexural

Strength Mortar Classa

(Environment) 28

days

MPa

91 days

MPa

28

days

MPa

91

days

MPa

(a) 2b:5 NHL5 Very High

(>50 cycles)

Very High

(>50 cycles)

Very High (>50

cycles)

Low -

Moderate

Very Low

(<51) 2 4

0.4

min 0.6

9 - 10

(severe)

2b:5 + 3% NHL5 +

pozzolan 8.4 16.8 3.5 5.7

9 - 10

(severe)

2b:5 + 6% NHL5 +

pozzolan 11.4 22.8 3.9 6.4

9 - 10

(severe)

(b) 2b:5 NHL3.5 High

(26-50 cycles)

Very High

(>50 cycles)

High

(26-50 cycles) Moderate

Moderate

(76-100) 1.5 3

0.35

min 0.5

5 - 6

(moderate)

(c) 1:1:6 NHL5

:Putty

Low

(<10 cycles)

High

(26-50 cycles) Low (<10) High

Very High

(126-150) 0.50 0.35

1 - 2

(passive)



December 2013 18

Mix

R

e

f

:

Cement:NHL5:

Sand

Illustrative Compressive

Strengths (MPa) Mortar Class1

It is anticipated that cement-based mortars will be used infrequently as cement-based mortars

are not suitable for use in arch barrels and should only be used where it is considered that its

use is justified on strength grounds where no movement/flexibility in the stonework is

anticipated. 7 days 28 days

(d) 1:1:6 5 7.7 9 - 12

(e) 1:2:9 5 7.7 5 - 7

a Mortar Class refers to definitions contained within IS EN 998-2 which specifies the constituent materials & performance requirements for mortar

for masonry. Generally when work is planned to continue beyond the Autumn raise the mortar durability class by at least 1 where the background

type permits. Where the background does not permit, plan work to commence in the early spring and be complete before the end of the summer.

b Volumes are based on lime with a Relative Bulk Density of 0.636kg/dm

3. Limes from other manufacturers will have different RBD's and the mix

ratio should be revised accordingly to provide a mix with similar performance values.

Ionad Ghnó Gheata na

Páirce,

Stráid Gheata na Páirce, Baile Átha Cliath 8, Éire

www.tii.ie

+353 (01) 646 3600

Parkgate Business Centre,

Parkgate Street,

Dublin 8, Ireland

[email protected]

+353 (01) 646 3601