Which aggregate under block paving?
Aggregate under block paving has to suit the whole pavement structure. The bedding layer and the sub-base do different jobs, so do not treat them as the same layer. The ground, the expected traffic and the requirements for the paving all matter.
Before you order sand or a sub-base mix, agree the type of material, the finished thickness and the quantity with your contractor. The question “what goes under paving?” on its own does not say whether you are building a footpath or a driveway for cars.
Sub-base and bedding layer
The sub-base helps to carry the loads and to provide support for the paving. Its design should take the ground and the traffic into account. The bedding layer is the layer in which the blocks are laid, in line with the chosen method.
A thicker bedding layer is not an automatic way to make up for a missing sub-base. If the ground is weak, the solution needs an assessment, not just more of whichever material you have chosen.
Footpath and driveway
A footpath carries different loads from a drive used by cars or by heavy delivery vehicles. That is why the thicknesses and properties of materials should not be carried over from one use to another.
Our range includes sand, crushed aggregates and sub-base mixes. Whether a particular fraction is suitable for a layer has to be confirmed. See our aggregates.
Compaction, slopes and common mistakes
Your contractor should choose the compaction method to suit the material and the layer. Simply smoothing the surface does not prove that it is ready. Slopes and drainage should be part of the pavement design.
A common planning mistake is ordering material before the layers have been decided. Another is calculating quantities without distinguishing between loose and compacted thickness. Confirm the solution first, then work out the tonnes.
How much should I order?
Multiply the area by the thickness of the relevant layer in metres. Convert the resulting volume into tonnes only using data for the material. Calculate each layer separately. Converting aggregate quantities.
Questions about block paving
Is sand alone enough?
Do not automatically treat it as the whole structure under the paving. The layer structure depends on the ground and the loads.
Can gravel replace the material specified in the design?
A change requires the properties and the method to be confirmed. A similar particle size does not mean identical behaviour.
Does delivery include compaction?
Buying the material and doing the work are separate scopes. Whether the work can be carried out has to be confirmed.