Aggregates

Aggregates are available to collect at all our branches. All standard building aggregates such as ballast, building sand and cement are available, along with bags of ready mix post mix that are ideal for setting in fence posts and decking posts. Two sizes of gravel, M.O.T type 1 and Coldlay Tarmac also available.

Many of these products are available in standard bags or bulk bags depending on your requirements. Please ask for further information and availability.

Aggregate guide.

What aggregates do I need?

Postmix

Postmix (Post Crete) is a premixed ready to use bag, for setting in fence posts, gate posts, pergola posts and similar uses, It is fairly fast setting and you only need to add water.

Ballast

Ballast is a mix of aggregates including sharp/grit sand and small stones or gravel it comes in a bag or a bulk crane bag and is used for mixing up concrete.

Cement

Cement is crushed limestone and other blended materials ground into a powder. It sets hard and is used to bind other materials together when making concrete.

Building sand

Building sand is a soft mortar sand used for bricklaying and pointing when a smooth finish is required. It can also be used under slabs and paving joints. Normally used when more flexibility and smoothness is required.

Sharp sand

Sharp sand is a washed concreting sand, suitable to use for making concrete when mixed with gravel and cement. It is ideal for bedding flagstones, block paving  and general building use. Also used for fine concrete work, rendering and internal floor screeding. Normally used where more strength and less flexibility are required.

10mm Gravel

10mm Gravel is suitable for laying pathways and drives as well as mixing fine concrete when a smooth finish is required.

20mm Gravel

20mm Gravel is also suitable for laying pathways and drives but used more when mixing up high strength concrete mixes.

Cold lay tarmac

Cold lay tarmac is ready to use, straight from the bag for quick, cost-effective repairs to paths, driveways and roads.

MOT Type 1

MOT Type 1 is granular sub base material used in the construction industry which is easy to compact and has high load bearing capability. It is as a sub base for highways, car parks, footpaths, drive ways and building bases.

How to mix concrete

Concrete is a mixture of cement, sand (fine aggregate), small stone or gravel (coarse aggregate) and water. A general purpose mix is used for  setting in fence posts and decking posts, constructing garden paths and foundations for retaining walls.
A medium strength general mix is known as a C20 mix this is made up of:-

C20 Concrete mix ratio

  • 1 x cement
  • 2 x fine aggregate (sand)
  • 4 x coarse aggregate

If you are using premixed bag of ballast, then 6 of these are mixed with 1 part cement.

A water to cement ratio of approximately 0.55 should be used so for 20kg of cement (20x 0.55 = 11kg (litres of water) this is the maximum amount of water that should be used.