Mortar: what are my mixing quantities?

Mortar must not be used after it has started to set, which usually occurs about two hours after it has been mixed. One man – particularly if he is a weekend builder – can probably lay a little more than 60 bricks an hour. If you are working on your own or with one assistant, it is better to mix a number of small batches as they are required than to mix a one-bag batch. Do not use too thick a layer of mortar between bricks or blocks; this is wasteful and may lead to cracking.

Mortar class

• Class I:  Highly stressed masonry incorporating high-strength structural units such as might be used in multi-storey load-bearing buildings; reinforced masonry.
• Class II: Normal loadbearing applications, as well as parapets, balustrades, retaining structures, and freestanding and garden walls, and other walls exposed to possible severe dampness. In practice, Class II mortars are used for most applications.

The amount of water added to a mix must be enough to make the mix workable and plastic

Masonry cement must comply with SANS 50413-1: Strength class 22,5X. The addition of lime to masonry cements is not permitted

MORTAR:

• For laying bricks and blocks in normal applications (SABS Class II)
• To lay 1000 bricks = 3 bags cement + 0.6 cu. m. sand
• 1 Bag of cement to 3 wheelbarrows of building sand

PLASTER:

• For exterior and interior work
• To lay 100sq.m. (15mm thick) = 10 bags cement + 2 cu. m. sand
• 1 Bag of cement to 3 wheelbarrows of plaster sand