Build Brick WallingMortars

Tutor Copy

Below are some web sites that may be useful for students studying construction:-

• www.ibstock.co.uk Bricks and related sites.• www.bca.ogr.uk British Cement Association• www.buildingdesign.co.uk Building design services • www.igltd.co.uk IG steel lintels.• www.catnic.co.uk Catnic lintels.• www.constuction-index.com Manufacturers• www.mortar.org.uk Mortar industry

association.• www.insulation-installers.co.uk Directory and related

links.• www.trada.co.uk Timber research• www.tra.org.uk Timber trussed rafter • www.hse.gov.uk Health & Safety Executive.• www.ucatt.org.uk Union of Construction Allied Trades & Technicians.• www.cskills.org.uk ConstructionSkills.• www.sheffield.gov.uk Planning application

information.• www.ebuild.co.uk Self-build / land for sale etc.

Mortar

Characteristics of Materials

General purpose mortar can consist of:• Sand.• Ordinary Portland cement.• Water.• Plasticiser.• Retarder.• Accelerator.• Pigments or colouring agents.

Requirements of a Mortar Mix

• The main requirement of a good mortar mix is workability.

• Bricklayers require a mortar mix which is described as ‘fatty’. This means it hangs on the

• trowel without being sticky, it spreads easily and it does not stiffen too quickly or too slowly.

• The mortar should meet other requirements to ensure that it retains its strength and

• durability during the life of the brickwork or block work.

These requirements include:

• Adequate compressive strength.• Adequate bond strength between mortar and bricks.• Durability – resistance to frost and chemical attack.• Joints sealed against wind-driven rain.• An attractive appearance.• The ability of the mortar to meet these requirements will

depend upon:-• The materials specified for the mix.• The workmanship of the bricklayer.• The protection of the materials and brickwork against

adverse weather.

JOINTING & POINTINGWhen bricks have been laid to form a wall, the surplus mortar is scraped flush with surface of the brick face. This type of surface finish is called

Flush Finish.

Why Point• The main purpose of any joint finishing is to

improve the wall’s resistance to rain or the ingress of water through the joint, as well as enhancing the appearance of the wall.

• This is achieved by packing mortar into the joints so that it has close contact with surface of

the brickwork.• Jointing up brickwork is a critical part of building

face work, and it should not be hurried.

• One of the most important aspects of jointing up brickwork is to avoid smudging or staining the surface of the bricks.

• Timing is probably the most important aspect of jointing up. The correct time to joint-up will be determined by the suction rate of the bricks being used and the weather conditions when the bricks were laid.

• The consistency of the mortar is also crucial as to when pointing takes place. If the mortar is too wet, the joint will not be crisp and the mortar may be dragged out from between the bricks.

JOINTING• The term used for ‘finishing off’ mortar

joints, of the brickwork, before the mortar hardens. (as the work proceeds)

Profiles of Mortar Joints

Keyed / Half round

Raked or square-recessed

Weather struck

POINTING• Cutting out and pointing back at a later

date

TO RE-POINT AN EXISTING PROPERTY

• Carefully remove old mortar, to a depth of 10mm, trying not to damage the surrounding bricks.

• The old mortar must be removed ‘squarely’ off all the brick arrisess.

• Use a sharp plugging chisel or hand grinder. • Wear the appropriate P.P.E. and consider

other people.• Remove all traces of old or loose mortar and

brush joints well, to remove dust. Work from the top, downwards.

• Mix mortar to specified mix and workability. ( 1:4 )

• Use a fine water spray to dampen joints for a small area (0.5 square metres)

• Using pointing trowel and hawk, force mortar fully into joints and neatly finish off.

• Protect pointing from weather, until set.