bricklaying manual

8/13/2019 Bricklaying Manual

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Laying the bricks

Preparation and procedure

Order all your materials-bricks, sand, cement, DPC rolls, door- and window-frames andlintels - well before you plan to start bricklaying. Have old sacking or polythene sheet tohand for covering work overnight in case of rain or frost.Choose a mortar mix to suit the type of work, the type of bricks you are using and theweather.Remember that frost is a danger until the mortar is cured and this can take several days.Do not mix more mortar than you can lay in one working session; two barrow-loads areusually enough. Mix the mortar on a large, dry, clean and level surface such as a sheet ofply or asbestos board.

Before starting work, place spot-boards alternately with piles of bricks at 3 m. (10 ft)

intervals near the building-line.

In hot, dry weather, hose down the bricks; if they are too dry they will absorb too muchwater from the mortar, thereby weakening it. Spot-boards should be dampened for thesame reason.

Keep a bucket of clean water handy for cleaning tools as you work. Mortar driesout your skin, so try not to handle it or, if you do, wear industrial or rubber gloves.


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Laying bricks on to a prepared concrete base slab is simply a matter of working accuratelybetween uprights. The more normal method -working up from concrete footings-is a littlemore complicated and is shown in the adjoining step-by-step picture sequence. For thesake of clarity, this has been shown starting from surface level, though footings are alwaysbelow ground level.Build up the corners or stopped ends first, taking meticulous care to ensure that they arevertical. The lines and pins are then strung between them and used as a guide to buildingup the courses in between.Then, if you are building higher, raise the corners or ends again and proceed as before.


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Arches, doors and roofs

Decorative arch

Building a load-bearing arch is beyond the scope of the amateur. A decorative arch is notdifficult, however.

Use a length of black mild steel as a support for the brickwork. If the wall is 112.5 mm.thick, use a piece of steel 50 mm. (2 in.) wide and 9 mm. (3/8 in.) thick; for a 225 mm.thick wall, use a piece 150 mm. (6 in.) wide.

Bond it in place in the sidewalls, then build up the brickwork. Use standard bricks on endwith wedge-shaped mortar beds between them. The sidewalls can be carried up and overthe arch, or the arch can be finished with a weatherproof bed of mortar on top. Fix door-and window-frames to brickwork with galvanised frame cramps, screwed into the frame

and bedded into the mortar.

Use a board and bricks to keep frames upright. When you build up to the top of the frame,mortar in the lintel. Lintels must overlap the frame 112.5 mm. (41/2 in.) each side forwindow- and door-frames.

Roofing

A felt and granite-chip roof is suitable for lean-to brick structures.Lay a course of cut bricks (1) on the top of each end wall to form a slight slope. Bed 100 x50 mm. wooden wall plates (2) on a 12 mm. (1/2 in.) mortar bed on top of each wall.

Fix a 100 x 50 mm. plate to the existing house wall with rag bolts, its underside level withthe undersides of the adjoining wall plates.Nail 100 x 50 mm. rafters (3) approximately 400 mm. (16 in.) apart between the side wallplate and the house wall plate, half-lapping them on to the house wall plate. Fix the firsthalf way between the end wall plates and work out from it.Nail 100 x 50 mm. noggings (4) at 600 mm. (2 ft) maximum centres between the rafters.Nail the end rafters to the projecting noggings, leaving the rafters just overlapping the

structure.


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Nail the fascia board (5) to the projecting ends of the rafters. Nail rectangular end pieces(6) to the end of the rafter overhang to give a level fixing for the soffit (7), fix the fasciaboard and then the soffits.

Cover the whole roof skeleton with20 mm. flaxboard (8); fix edging battens (9). Clout-nailthe first felt layer, bond on the second layer of felt with brush-on bituminous-based liquid,fix the mineral felt drips to the edges and bond the third and final felt layer. Overlap thejoints in the felt; make sure joints in each layer do .not coincide. Scatter granite chips overthe top layer after coating with bitumen.Seal the joint between the roof and house with a flashing of mineral felt mortared in thehouse wall and stuck on to the felt.

Lintels

Spanning openings above door and window frames

Brickwork above a door or window frame must be supported by a lintel, which may beeither of reinforced concrete or of galvanised steel. Both types are made to span openings

in 112.5 mm. and 225 mm. solid walls and in 337.5 mm. cavity walls. Lintels will beneeded for such jobs as building a brick garage, outhouse or kitchen extension. They can


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be bought from builders' merchants. Since concrete lintels of all but the smallest sizes arevery heavy, do not attempt to fit one without help and then not unless you and your helpercan, each on his own, lift the lintel without undue strain. To allow a proper margin ofsafety, work from a stoutly built platform or from scaffolding, with two thicknesses ofscaffold boards so that you do not need to lift the lintel above waist height. If this is not

practicable, then the job is best left to a builder. A concrete lintel is visible unless thebrickwork of the wall is rendered, in which case the face and the underside of the lintelshould also be rendered.A steel lintel has the advantage of not showing on the face of the brickwork, and is alsomuch lighter than a concrete one.Two types of steel lintel are manufactured for use in cavity walls. The Standard lintelcannot be used alone but must be supported by a concrete lintel on the inner wall of thecavity. The Combined type is more complex in design and supports both the inner and theouter wall.


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Buy a lintel at least 300 mm. (1 ft) longer than the gap to be spanned, for at least150 mm. of it at either end needs to rest on the supporting surface.Lintels, whether of galvanised steel or of concrete, must rest on a complete brick, or block,at either end, so plan accordingly when building up courses of bricks or blocks. Bed thelintel on to mortar, making sure that its weight is borne solely by the brickwork; at no point

should it rest on the door or window frame. If the frame is too high, bed a piece of slateinto the mortar on the brickwork, to build up its height. Finally, squeeze a mastic sealerinto the space between the lintel and the top of the frame; the mastic will remain flexibleand will not harden or crack.

Repointing

Tools neededCrumbling mortar joints in old brickwork allow moisture to penetrate the wall. The remedyis repointing - clearing out the old mortar to a depth of about 15 mm. (1/2in.), and thenreplacing it with a new waterproof mortar joint. If you are repointing the whole wall, the

job can be done in stages, tackling about 1 sq. m. (1 sq. yd) at a time and completing thewhole wall when you can. Always set up a platform for high walls, so that you work atchest level-do not try working on a ladder.When repointing, you should match the composition of the new mortar to the old.

If you do not know the mix for the old mortar, make the new mortar of 1 part lime to I partcement and 6 parts builders sand (1:1:6).

Types of joint

If you are patching a wall, match the new joints with the existing ones. For example,

Form flush joints on a wall, which already has them.


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If you are completely repointing, or putting joints in new brickwork, use any of the jointsshown here.Weather-struck joints give the maximum protection from damp and so are worth the extratrouble, especially on chimneys and house walls. Recessed joints look effective with roughtextured bricks; flush or rubbed joints are better with smooth-surfaced ones.


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Bricklaying - Getting started

If a simple brick barbecue or a small

retaining wall is needed, why not

give it a go.

Follow our basic bricklaying guide and a leaning tower of Pisa is easily avoided!

Know your bricksBricks are either extruded (top pic) or dry pressed (below).

Dry pressed bricks have a frog,are very porous and have to bedampened (not soaked) beforeuse for maximum mortar strength.

They are easily cut with a lump hammer and bolster. Extruded bricks have holesthrough them and must be laid dry. A brick saw may be needed to cut them.

There are also lower-quality 'commons' (common bricks) used for internal walls

and walls that will be cement-rendered and high-quality face bricks for externalwalls and structures.

Specialist brick types include sandstock bricks, concrete blocks and shapedbricks, including bullnose and sill.

A half brick is known as a bat.

Brick terms (left to right)


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Soldier stood on end.Stretcher - laid lengthwise in a wall.Header laid through a wall, at right angles to stretchers.

Brick bondsFor a wall to have maximum strength, bricks must be lapped one over the other

in successive courses. Poor bonding can lead to cracks or weakness. Precisionis very important and brickwork must be checked frequently for plumb (vertical)and for level. Types of bond include:

Stretcher bond (top pic) is also called half bond and is used in all generalconstruction.

Stack bond (middle left pic) is laid vertically on top of each other and is a veryweak bond only for feature panels or low fences.

English bond is also called quarter bond (middle right pic) and is alternate

courses of headers and stretchers, for retaining walls.

Header bond (bottom pic) is laid as headers and used most often for circularwalls or curved brickwork.

Brick drivewaysBricks need a substantial base to bear the weight of vehicles. Usually 100mm ofwell compacted roadbase under 50mm of bedding sand will do. For a heavy-duty


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driveway, use a base of 100mm of concrete under the sand.

Types of bricks(top to bottom)

Below left:

Interlocking clay paverClay paverOrange extruded common brickShaped brick for cornersDouble bullnose for capping

Below right:

Secondhand original sandstock brickDry pressed face brick in the sandstockrangeBrown dry pressed face brickCream dry pressed face brickCream mottled clinker (very hard fired)brick


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Mixing mortar

It's mortar that holds your bricks

together. Here's how to get the mixright.

The mixA general-purpose mortar is six parts bricklayers sand, one part cement and one

part lime (6:1:1).

A plasticiser can be added to make the mortar more workable and awaterproofing agent is added to mortar for brick fences to prevent damp.

Sand is normally sold by the cubic metre or tonne. One cubic metre of sandweighs roughly 1.5 tonnes.

Keeping the mortar at the right consistency is part of the art of laying bricks. Themortar holds the bricks in place and levels the courses. It should be soft andpliable and not too dry, a bit like toothpaste.

Mortar is good for one and a half hours (add a little water to keep it soft andworkable) before it loses elasticity and should be thrown out.

You'll need:Bricklayer's sand (70 per cent bush sand and 30 per cent sharp sand), cementand lime, or pre-mixed mortarPlasticiser, waterproofing agent and oxides (optional)Wheelbarrow, plywood or concrete mixerShovelMortar board

TrowelJointer or raker

Here's how:1. When mixing by hand, thoroughly mix the ingredients dry before adding water.The mortar should finish an even colour. In a concrete mixer, put the water infirst, then the sand, the cement and finally the lime, topping up with water ifneeded.


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2. Transfer the mixed mortar to a mortar board. Mortar boards are about onesquare metre and made of waterproof plywood or a light steel plate. Keep themortar on the board soft and pliable by working it continually with the trowel.

3. Trowel the mortar off the board with a smooth wrist, elbow and shouldermovement.

4. Using the tip and edge of the trowel drop and move the mortar left, then righton the board to get an even consistency.

5. Using the back of the trowel, move the mortar back across the board to finishthe mixing.

Mortar joint types

Different mortar joints are shaped while the mortar is wet:Flush joint - cut flush with a trowel.Round ironed joint - using a round iron jointer; used in restoration work onFederation houses.Raked joint - using an adjustable raker up to 10mm deep; used in house


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construction.

Other common types include struck joints and weather struck joints, made byrunning the edge of a trowel along the joint.


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Build a brick wall

There are a few tricks to

building a good-looking brickwall, so follow our step-by-

step guide.

Here's how:1. Start laying at the lowest point. Always construct a corner first. Rack (step) outabout three brick lengths and take the corner up six courses. Use a string lineand line pins from the corner to keep the brickwork straight and level. Check thealignment with a straight piece of timber.

2. Keep the bed and cross joints an even 10mm. Lay one course, from corner tocorner, before moving up to the next course. Always keep the corners higherthan the rest of the brickwork. Fix string lines and corner blocks to keep eachcourse straight and repeatedly check the level and plumb, tapping bricks intoalignment with your trowel.

3. Finish the mortar joints while the mortar is wet. For round iron jointing, finishafter every second course; finish rake joints every four or six courses.

4. If you need to step up brickwork, always use two level string lines. Lay onestringline at the top across the stepped gap, from the end of the built-up wall to acourse above the step; lay the other line on the lowest course so that thebrickwork runs into the step evenly. Cut the lowest course if necessary to makethe top course level.


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Wall junctionsTie side walls at least 110mm into the main wall as the wall is being built. If youare unable to build the junction walls at the same time as the main wall, leave tie-ins (indents) and build the junction walls later. (illo a p 29) (illo b p29)

Damp-proofing(illo a p30)

A damp course stops water rising up the wall or crossing a cavity from theoutside to the inside wall above windows and doors. In domestic construction, adamp-proof course (DPC) is laid three courses above ground level or at floorbearer height. Flashing is laid under all windows and on top of all windows anddoors. Extend it a minimum of 100mm past the frame into the wall. For on-slabconstruction, leave a rebate around the edge of the slab. Place the flashingdirectly on the slab and turn it up the rebate and through the wall. To completelyseal off the slab it must overhang the plastic membrane.

DrainageYou may need to provide drainage: agricultural pipe and rubble drains to removeground water, or surface drains, such as spoon drains, to divert run-off awayfrom the structure. Weep holes are left in walls to allow water to drain out.

Circles and curvesTo set out a circle, fix a stake in the centre and tie a piece of string the radius ofthe circle to it. Attach a metal stake to the other end and draw the circle.Determine the width of the foundation trench, adjust the string and draw circlesfor either side of the trench.


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Set out curved walls in the same way, but draw only the required part of thecircles. Curved walls are most easily laid in header bond. For curves of smalldiameter, bricks can be cut to a tapered shape. Common bricks and tapered

joints can be used for curved walls with a diameter greater than 2m.


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Building and pouring

With the trenches dug, the next step

is to mess around with concrete.

You'll need:Timber for formwork

Timber stakes, nails and hammerSteel reinforcement (mesh or bars, stirrups and bar chairs)Tie-wire and pliersCement, sand and coarse aggregateConcrete mixer (optional)Wheelbarrow, shovel and gumbootsStraight edgeSteel and wooden floats

Steel reinforcementConcrete should be reinforced with two layers of steel bars or trench mesh,

placed as near the top and bottom of the concrete as possible and at least 60mmfrom the edges. Hold the bars in place with stirrups suspended by wire fromtimber beams and overlap joins by 450mm.

The concrete mix (4:2.5:1)


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When mixed, the concrete should hold its shape without slumping (too wet) orcrumbling (too dry). The usual mix is four parts coarse aggregate, such as gravel,two and a half parts sand and one part cement (4:2.5:1), with enough water toget it to a plastic state.

You can have ready-mixed concrete delivered in multiples of 0.2 cubic metres.When ordering, advise the type needed (whether it's for footings or slab, etc).

QuantitiesPer cubic metre of concrete you'll need 0.8 cubic metres coarse aggregate, 0.5cubic metres sand, six and a half bags (40kg) cement.

Hand mix ingTo mix small quantities of concrete, you'll need a shovel, a metal wheelbarrow ora flat, easily cleaned surface.1. Thoroughly mix the cement, sand and coarse aggregate together while they

are still dry.2. Make a well in the centre of the dry mix. Add water and combine until the mixhas achieved an even colour and texture.

Using a concrete mixerTo mix concrete in a concrete mixer, make sure the mixer is level and on a stablesurface.1. Begin with two buckets of water in the machine.2. Add four buckets of aggregate.3. Add two and a half buckets of sand.4. Add one bucket of cement.5. Add water and mix until an even colour and texture (at least three minutes).

Pouring the footingsPrepare any formwork the day before and have all the equipment you'll need tocarry, spread and level the concrete ready before you start. Get going early tohave concrete set before dark.

Here's how:1. Start pouring concrete at the lowest point on the site and spread it with ashovel. Regularly check the level as you go. Make sure the concrete is packedunder the steel reinforcement so it doesn't drop. If the stirrups are suspendedfrom a beam, cut the tie-wire with the shovel as you work. Step the footings ifnecessary.

2. Finish the concrete about 100mm below ground level and smooth with a float.A steel float gives a smoother finish than a wooden float.

3. Leave to cure for at least two days or the concrete may crack.


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Setting out Foundations

The key to any successful

construction is starting with a strongbase - the solid foundation.

Here's what you need to know about seting out foundations, including levels,trenches and formwork.

You'll need:Measuring tapeTimber stakesTimber for profilesNails and hammerStringSpirit level and line level12mm clear tube water level or dumpy level (optional)

Plumb bobBuilder's squareSpade

Here's how:1. Erect timber profiles 1m beyond the outline of the job. Tie string lines to thenails in the profiles to act as guides to the width of the foundation trench andwalls.

2. Ensure the corners are 90 degrees with a builder's square or use the 3-4-5method. From the corner measure down one side 3m and down the other side

4m (or any multiple of these). The hypotenuse (or diagonal) should equal 5m ifyou've made a right angle.

To be accurate, measurements should always be taken on the level, even on aslope. Use a spirit level to ensure the tape measure is level.


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Establishing levels3. Accurate levels are essential. Put a timber stake in the ground at each cornerof the job. Put a mark on one stake and carry it around to the other stakes, usingyour choice of level to adjust the string lines to the same level.

Hire a qualified surveyor for large projects and any work near boundaries.

Foundation trenches and formwork4. Concrete footings are usually twice the width of the wall and as deep as they

are wide.

To find the level for the top of the footings (about 100mm below ground level),measure down an equal distance from the level mark on each stake. If theground is not level, step the footings.

5. Dig within the string lines, keeping the sides of the trench vertical and straight.

6. If the footing rises above ground level, you'll need to erect temporary formworkto hold the concrete in shape until it hardens. The formwork foundation trenchshould be 100mm wider than the footings.

bricklaying manual

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