Stepwise preparation of cement mortar

Cement mortar is prepared by hand mixing for small jobs or by a mixer for large works.

Steps

1. Select the proportion (by volume), for example 1:6 (or 1:4) cement:sand for brick masonry and 1:4 to 1:6 for plaster; select the sand (clean, sharp, free from clay and silt).
2. Measure the materials by volume using a gauge box (usually 35 litres, the volume of one 50 kg bag of cement).
3. Mix dry: spread the sand on a clean, watertight platform (wood or concrete), spread the cement on top and turn the heap with shovels 3-4 times until the colour is uniform.
4. Add water gradually, just enough for a workable mix, while mixing again: form a crater in the heap, pour water into it and turn the dry mix into it. Do not over-wet.
5. Mix thoroughly until a uniform, workable paste of the right consistency is obtained. In machine mixing, load the sand and cement, add water and mix for at least 3 minutes.
6. Use within 30 minutes (before initial setting). Do not re-temper or use mortar that has begun to set, and keep the platform clean.