About Sands and Aggregates

Aggregate is a mixture of sand and stones that is added to cement with water to bring about hardening. Aggregates are vital to most building projects. Whether you're laying a patio, building a wall or rendering a surface, some form of aggregate will be required.

While it is possible to mix the stand and stones yourself, aggregate can also be bought ready-mixed, which may be preferable for small repairs. Self-mixing gives you the flexibility to vary the proportions of the mortar according to the demands of the specific job, with the type of aggregate used dependant on the size and shape of the material.

Aggregates are differentiated by their coarseness. The crushed stones and gravel are passed through different sized sieves, allowing you to determine the maximum size of stone you wish to be retained in this process.

- Builders / Bricklayers / Soft Sand – This is the finest grain of sand commonly available and the best kind to use in mortar mixes for pointing and filling cracks. Silver sand makes for a lighter coloured mortar, worth bearing in mind if you are using white screening blocks.

- Sharp Sand – Sharp sand is classed as a coarse material and is most appropriate for use with concrete.

- All-in Aggregate / Ballast – Pre-mixed combination of sharp sand and stones. For small repairs / cracks use one part cement to 3 or 4 parts all-in aggregate. For foundations use one part cement to 4 or 5 parts all-in aggregate.

- 10mm – maximum stone size is approx 2/5 inch. This is suitable for pathways and the like.

- 20mm – maximum stone size is approx 3/4 inch. This makes for the coarsest form of aggregate available and is only used for very heavy work.

Foundation work will require a very coarse aggregate. Use a proportion of 1 part cement to 2 parts sand and 3 parts stones.

Most builders’ merchants can supply a wide variety of aggregates loose or bagged in a range of quantities. Decorative aggregates are also commonly available.