Sand comes in a wide range of sizes, colours and qualities. It is important to recognise these different types and the different projects that they are used for:
‘Normal’ grey building sand comes in two main categories. Sand to be used for making concrete contains a lot of large, very rough particles – strictly, particles larger than 6.3mm diameter. Sand to be used for mortar, as used for brick-laying etc has less of the large grit in it. Both of these types of sand are usually bought by the cubic metre, and are best suited to large building projects.
For smaller jobs, the choice is usually between medium, fine and very fine. Thes will have been carefully wahed, dried and graded. The fineness of the sand used determines how smooth the resultant mix is, since neither lime or cement add to the graininess of the mortar used.
Very fine sand
Very fine sand comes from a quarry. It is very pale, with grains 0.1 – 0.3 mm in diameter. This sand is used occassionally for very fine cement work, but is used also for polishing and cleaning. There are few jobs which require a large quantity of this sand.
Comes from either a quarry or a river. Usually very pale brown, with grains 0.2 – 0.6mm. This fine sand is used for sandblasting and hydro-sandblasting (sandblasting with a mixture of sand and water), on materials such as wood and metal.
Sand for sandblasting is usually silicon rich – often labelled ‘sable naturel a quartz’ or similar.
Also from either a river or a quarry. Light brown, with grains of diameter 0.4 – 1.6mm. This is usually used for sandbasting stonework and masonry, when the wall is sufficiently stable to support it.
The colour of your sand is important when the final product will be visible – for example if you are repointing a wall. The colour of the sand that should be used is very specific to your immediate region so you will need to take advice from a local builders merchant.