This calculator will provide the approximate quantities of sand & opc for Class II
mortar per square metre of metric brickwork.
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Good Practice
Brick Mixing
Natural materials such as clay bricks have characteristic variations in shade, colour and texture. However
because patching or colour banding would not be desired in the finished work, it is important to blend the bricks.
Although this is carried out at manufacturing there is still a need to further carry out this process on site,
this is best achieved mixing from as many packs as possible and mixing from corners rather than layers to maximise
colour consistency.
Mortar
The correct preparation is key to the overall aesthetics, durability, weather resistance and structural
performance. See our other brick calculator for further info on mortar. In general terms the correct proportions of
binders and sand is necessary for consistent mortar strength, avoidance of colour variation and a good bond between
brick & mortar. This should be achieved by the use of batching boxes or buckets, avoid the use of shovels for
proportioning by volume.
Bricklaying
- Mortar consistency In general, the correct mortar consistency is a matter of the bricklayers judgement.
However, if mortars are too wet at the time of laying this can lead to staining of the brick edges and, in the
worst cases, runs of mortar can form on the face of the brick. Ideally, mortar should 'hang' on the trowel without
being sticky, should spread easily and should not ooze out of the joints when bricks are positioned
- Docking It is accepted practice for bricks with a high absorbency to be wetted prior to laying. This procedure
adjusts the suction rate of the brick to promote good adhesion between the brick and the mortar. However, bricks
should not be soaked during the process as this could lead to subsequent staining problems. See above. Bricks with a
low suction rate should never be wetted because they might 'float'; mortar that is mixed too wet will have the same
effect
- Tooling The bricklayer uses his skill and experience in determining when to begin tooling the joints after placing
the bricks in mortar. Early tooling should be avoided as this can produce a dragged effect on the mortar surface and the
cement fines may be drawn to the surface resulting in an unsightly patchy bloom on the joints in the mature work
- Winter working If the temperature of unhardened mortar is less than 4oC, the performance of the joints produced will
be inadequate. Consequently, bricklaying should stop when the air temperature reaches 3oC and falling, unless the mortar
temperature can be maintained at a minimum of 4oC until it has hardened. Bricklaying can be resumed when the air temperature
rises to 1oC and is expected to continue rising to above 3oC over the bricklaying period