ISSUE 06/08

BRICKWORKBrick sizes vary slightly because of the way they are made but for ease of calculationthe size of one brick is taken as 215 x 102.5 x 65mm and for normal brickwork thejoint between the bricks both vertically and horizontally is 10mm. When deciding how many bricks are required the thickness of the mortar joint isincluded into the calculations, making the measurement of the brick -225 x 102.5 x 75mm. By adding the mortar joint thickness any slight variations in sizefor the bricks is taken into account.

When determining how many bricks are required you should first work out the area ofthe brickwork as follows:- Length of wall say 4m, height of wall say 0.5m, multiply thetwo figures together, 4m x 0.5m = 2 square metres. Square metres are often writtenas ‘m2’ or ‘sq.m’.

For an easy rule of thumb guide you should allow 60 bricks per square metre for thebuilding of a single skin wall. This is known as a half brick wall and is shown inDiagram 1. The style is known as Stretcher Bond with only the long ‘Stretcher’ facesof the bricks visible.

In the example above for a 2 square metre wall you will need to multiply 2 (area ofbrickwork) x 60 (number of bricks per square metre) = 120 bricks.

If you intend constructing a one brick thick solid wall, as shown in Diagram 2, thenyou should allow for 120 bricks per square metre. So for a one brick thick solid wallyou will need 2 (area of brickwork) x 120 (number of bricks per square metre) = 240bricks. The visible ends of bricks are known as ‘Headers’.

These figures do not allow for wastage or breakage, so it would be advisable to add afew extra to the order to make certain you do not run short. Normally 10% extrashould be sufficient.

CALCULATING BUILDINGMATERIAL QUANTITIESWhether building a wall inthe garden, laying a patio,adding an extension,converting a garage into anoffice or simply making aconcrete path, one questionis certain to crop up. “Howmuch do I need?” It isprobably one of the most

important questions and onethat tends to cause the mostconfusion when trying towork out the answer. If youare planning a garden wall,for example, you will knowthe length and the height,but how many bricks will benecessary? Even more

importantly, how many bagsof Wickes bricklaying mortarshould you buy? There isnothing more frustratingthan starting a job only torun out of materials part waythrough.

13

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MortarThe next question to be answered is, howmuch mortar will I need? Wickes baggedbricklaying mortar is supplied to thecorrect ratio for general bricklaying toensure a perfect mortar mix. (The weightof bags is approximately 25kg but thisdoes vary depending upon the moisturecontent.) With our bricklaying mortar allthat is necessary is for water to be added.However, if large quantities are required25kg bags of Mastercrete cement andMaxi bags of building sand are availablefor you to make your own mix.

A bag of Wickes bricklaying mortar issufficient for about 25 bricks, dependingon the thickness of the mortar joints, sofor a square metre of brickwork (60 bricks)2 - 3 bags will be required.

So to find out how many bags of Wickesbricklaying mortar mix are required for theexample wall measuring 4m long by 0.5mhigh and using 120 bricks we need todivide the total number of bricks (120) by25 (coverage of one bag):-

12025 = 4.8 so 5 bags of bricklayingmortar are needed.

If the wall is to be built one brick thickusing 240 bricks you would need:-

24025 = 9.6 so 10 bags of bricklayingmortar are needed.

To lay say 1000 bricks (16.5 square metres)as a single skin wall, approximately 0.3cubic metres of mortar will be needed, or40 bags of bricklaying mortar. If the wall isto be built as a one brick thick solid wallthen you will need 60 bags of Wickesbricklaying mortar.

NOTE: All calculations and quantitiesare approximate and the informationsupplied should be used for guidanceonly.

GeneralA bag of Wickes bricklaying mortarcontains all the necessary ingredients tomake a good quality mortar mix, which issuitable for most general purposebrickwork or blockwork. However, if youwant to mix your own mortar theproportions for most general bricklayingpurposes should be 1:5, that is one partMastercrete cement to five parts buildingsand for bricklaying.

The mix may vary slightly depending onthe type of structure being built. (Seechart at the end of this section). Themeasurements can be by weight or, muchmore easily, by volume, such as thebucketful, but they must be constant foreach batch mixed.

One 25kg bag of Mastercrete cementand 5 bags of building sand will make ageneral purpose mortar of 1:5 mix -enough to lay about 140 bricks or about35 concrete blocks.

If you are laying your brickwork in thecold weather, or are looking for greaterworkability and flexibility, Wickes MortarPlasticiser should be added to the

mixing water, in the amounts shown onthe packaging instructions. Theplasticiser produces tiny air bubbles inthe mortar to allow the water to expandin freezing conditions and to reduce thepossibility of the mortar cracking. Theplasticiser is the modern replacement forlime that was once used in mortar mixes.

NUMBER OF BRICKS & AMOUNT OF MORTAR REQUIRED (single skin of brickwork)

Sq.m. of Number of Bags of brickwork bricks needed bricklaying mortar

(rounded up)

1 60 2.4 (3)2 120 4.8 (5)3 180 7.2 (8)4 240 9.6 (10)5 300 126 360 14.4 (15)7 420 16.8 (17)8 480 19.2 (20)9 540 21.6 (22)

10 600 24

NUMBER OF BRICKS & AMOUNT OF MORTAR REQUIRED(solid one brick thick wall)

Sq.m. of Number of Bags of brickwork bricks needed bricklaying mortar

(rounded up)

1 120 4.8 (5)2 240 9.6 (10)3 360 14.4 (15)4 480 19.2 (20)5 600 246 720 28.8 (29)7 840 33.6 (34)8 960 38.4 (39)9 1080 43.2 (44)

10 1200 48

For concrete blocks the calculations are a lot easier. Wickes medium densityconcrete blocks and Wickes aerated concrete blocks measure 450 x 215 x100mm - both types can be used above or below ground.

You will need roughly 10 blocks per square metre of wall, and 2 bags ofbricklaying mortar will be sufficient for 10 blocks. So for every square metre ofblock work order 2 bags of bricklaying mortar mix.

NUMBER OF BLOCKS & AMOUNT OF MORTAR REQUIRED(single skin 100mm thick blocks)

Sq.m. of Number of Bags of Wickesblockwork blocks needed bricklaying mortar

1 10 22 20 43 30 64 40 85 50 106 60 127 70 148 80 169 90 18

10 100 20

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The amount of water needed to make aperfect mortar mix is also important. For abag of bricklaying mortar about 2.5 litresof water will be required.

However, water should be added first insufficient quality to allow it to be absorbedby the mix, then it is added little by littleuntil the mix has the consistency of butter- slipping easily from the shovel but firmenough for the sides not to collapse whena hollow is made in the centre of the mix.

Mortar should be used within two hours ofmixing, so only mix sufficient to be usedwithin that time. A rule of thumb estimateis that it takes about 2.5 minutes to layone brick. If the mortar stiffens slightlywhile you are working, bring theconsistency back by adding a little water.

If the mix is too dry it will not adhere to thebricks properly, if it is too wet the mortarwill simply ooze from the joint under theweight of the bricks.

In the mixes above, note the use ofdifferent types of sand.

Types of sand & aggregatesSand and aggregates are graded by thesize and shape of their particles. A wellgraded sand for example, will haveparticles of different sizes - not all largeand not all small.

Sharp sandA rather coarse and gritty material. It isnormally used with other, coarseaggregates for making concrete and floorscreeds.

Soft sandKnown as builders or bricklayers sand thishas smoother particles and is of a finergrade than sharp sand. It is mixed withMastercrete cement to produce bricklayingmortar.

The test of a good quality sand is that itshould not stain your hands when yousqueeze it.

Coarse aggregate (Not stocked on itsown by Wickes).Basically this is gravel or crushed stone ofsufficient size to be retained by a 5mmsieve up to a maximum size of 20mm. It isused to form concrete when mixed withsharp sand and Mastercrete cement.

BallastKnown as ‘combined’ or ‘all-in’ aggregate,this is a mix of sharp sand and coarseaggregate and is used for makingconcrete. The proportions of sand togravel are not normally guaranteed butare acceptable for use in a generalpurpose concrete mix.

StorageSand and aggregates should always bestored in a neat pile on a board or plasticsheet and should always be protectedfrom dirt and rain by covering with aplastic sheet. This should be weighteddown with bricks or similar heavy objectsto prevent it blowing away.

ConcreteConcrete is one of the most usefulmaterials that can be used around thehome. It can be used to create a pavedarea such as a path or driveway, or usedas foundations to support a wall. Concreteis normally made from three basicmaterials - Mastercrete cement, sharpsand and coarse aggregate. Mixedtogether the three ingredients form astrong and solid structural material.

A mix is generally expressed as, forexample, 1:2:4, which indicates 1 partMastercrete Cement, 2 parts sharp sandand 4 parts ballast (gravel). There arevarying mixes for different purposes andthese are indicated shortly.

When the sharp sand and gravel arepremixed this is known as all-in ballast (orall-in aggregate). In the example justdescribed the mix would be expressed as1:6 meaning 1 part Mastercrete Cementto 6 parts all-in ballast.

For convenience and to ensure a perfectmix, a bagged Wickes concrete mix isavailable. This has the correct amount ofcement and all-in ballast and all that isnecessary is for clean water to be added.Between two and three litres of water willbe needed for each bag of concrete mix.

As a rule of thumb, one bag of Wickesconcrete mix will cover an area ofapproximately 0.0125 m3. It is difficult to give exact figures as the sub-base forconcrete work, which is normallyhardcore or broken bricks, varies so muchin shape and has voids to be filled.

MixingThe ballast should be thoroughly mixedbefore the cement is added. Mix in thecement until the dry pile has an evencolour. Then the water can be added froma watering can. The mix is correct whenyou can make a series of ridges in the topsurface by dragging the back of the shovelacross. The surface of the concreteshould be flat and even and the ridgesshould keep their shape without filling in.

CHOOSING MORTAR MIXES FOR BRICKWORKType of construction Proportions of Mastercrete

Cement/Building SandExternal walls above d.p.c. level 1:5External walls below d.p.c. level 1:4-5Internal walls and inner leaf of cavity walls 1:6Coping stones and sills 1:3Parapets and domestic chimneys 1:4-5Retaining walls 1:3External freestanding walls 1:4-5Manholes 1:4-5

CHOOSING MORTAR MIXES FOR BLOCKWORKType of construction Proportions of Mastercrete

Cement/Building Sand

External walls above d.p.c. level 1:6External walls below d.p.c. level 1:5Internal walls 1:6Parapets 1:6External freestanding walls 1:5Manholes 1:5

CHOOSING A SUITABLE MORTAR MIX FOR RENDERINGBackground material Mix u/coat t/coat

Low suction such ashard dense clay bricksdense concrete blocksstone masonryconcrete Mastercrete cement /sharp sand 1:3-4 1:5

Normal suction such asaverage types of bricksclay blocks concrete blocks aerated concrete blocks Mastercrete cement /sharp sand 1:5 1:6

ALL RATIOS BY VOLUME

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Like bricklaying mortar, the mixed concreteshould be used within two hours. It shouldalso be noted that concrete dries fairlyquickly to give a hard top surface but willnot reach any real strength for at leastseven days.

The weather is an important considerationwhen laying concrete. The water in theconcrete mix must not be allowed toevaporate too quickly if the weather is hot,or freeze when the weather is cold. Oncelaid the concrete should be protected fromthe weather.

A polythene sheet laid over the surfaceand weighted down with bricks to stop itblowing away is ideal. This sheeting willprotect the concrete from rain and mostnormal frost attack. It will also helpprevent water evaporation in the summermonths if the weather is too hot.

If the daytime temperature reaches 20°Cor more, the concrete should also begiven a light spraying of water at leastonce a day for a week. The concreteshould be re-covered with the polytheneafter spraying, otherwise it may well crackand crumble.

In very cold weather add our RapidHardener and Frost Protective to the mix.This admixture reduces the initial andfinal setting time of concrete by about twothirds - helpful if frost is about.

NUMBER OF BAGS OF WICKES CONCRETE MIX REQUIRED

Major bags Produces approximatelyconcrete mix this amount of concrete

15 0.19 cu.m30 0.38 cu.m45 0.56 cu.m80 1.00 cu.m

As an alternative, if you wanted to make your own concrete you would need thefollowing:-

CONCRETE PATH. 8M LONG, 0.5M WIDE, 50MM THICK(using a mix of 1 part cement, 9 parts ballast - parts by volume)

Quantity Material2 25kg bag Mastercrete cement

17 Maxi bags all-in ballast37 litres clean water - approx.

Using totally separate materials this mix would normally be expressed as a 1:3:6mix meaning 1 part cement, 3 parts of sharp sand and 6 parts of gravel. UsingWickes bags of all-in ballast the ratio to get the same volumes is as shown in theexample.

APPROXIMATE QUANTITIES OF MATERIALS TO MIX YOUR OWN CON-CRETE

Bags of Bags of Water Produces thiscement all-in ballast litres amount of concrete

2 17 37 0.25 cu.m4 34 74 0.50 cu.m6 50 104 0.75 cu.m8 67 150 1.00 cu.m

As sand in the ballast tends to absorb moisture from the atmosphere it is betterto use different buckets for the ballast and cement, in order to keep the cementperfectly dry.

TYPES OF CONCRETE MIX

Use Normal Equivalent quoted ratios using

cement/ cement andsand/gravel. Wickes bagsRATIOS BY of all-in

VOLUME ballast

Foundations 1:11/2:3 2:8

Driveways, garageslabs and other heavy load areas 1:2:4 2:11

Paths, shed bases and other light loadareas 1:3:6 2:17

Blinding layer forsub-floors etc. 1:4:8 2:21

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DIAGRAM 1

DIAGRAM 2

STRETCHER FACE

HALF-BRICK WALL

ONE-BRICK THICK SOLID WALL

HEADER FACE

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WICKES JUMBO & MAJOR BAG COVERAGE AND VOLUME AMOUNTS

Whilst every care has been taken to ensure that the product design, descriptions, specifications and techniques of constructing the products are accurate at the date ofprinting. Wickes products will inevitably change from time to time and the customer is advised to check that the design, descriptions, specifications and techniques of

constructing any of the products described in this leaflet are still valid at the time of purchase or placing an order.© Wickes Building Supplies Limited 2008

All rights reserved. No part of this publication may be produced or transmitted in any form or by any means electronic, mechanical, photocopying, recording or otherwiseor stored in any retrieval system of any nature without the written permission of the copyright holder and the publisher.

Sku Jumbo Bag description m2 coverage at m3 per bag approximately approximately*50mm depth*

220081 Sharp Sand 11m2 0.55m3

220082 Ballast 13m2 0.65m3

220080 Building Sand 11m2 0.55m3

224555 Pea Shingle 13m2 0.65m3

224665 Granular Sub Base 12m2 0.60m3

190538 20mm Gravel 13m2 0.65m3

190537 Plastering Sand 11m2 0.55m3

190536 Cotswold Buff 12m2 0.60m3

Decorative Chippings

Sku Major Bag description m2 coverage at m3 per bag approximately approximately*50mm depth*

220081 Sharp Sand 0.3m2 0.0159m3

(as a render/floor screed)

220082 Ballast 0.35m2 0.0175m3

(as a coarse concrete mix)

220080 Building Sand 0.3m2 0.0156m3

224555 Pea Shingle 0.35m2 0.0175m3

(as a fine concrete mix)

220189 General Purpose Concrete 0.24m2 0.0137m3

Sku Major Bag description m2 coverage at m3 per bag approximately approximately*15mm depth*

190537 Plastering Sand 0.7m2 0.0105m3

Sku Major Bag description m2 coverage depends N/Aon block/bricktype/size*

220201 Kiln Dried Block Paving approx 3-6m2

Sand Major Bag

220174 Bricklaying Mortar will lay approx 33 bricks

*Important: All coverages and volumes are approximate and for guidance only, they depend on the bulk density of the product relating to compaction and in the case of sand; moisture content and compaction.

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