Paver Calculator

Typically 25 to 40 mm, screeded to a consistent depth rather than spread. Variation in the bedding shows up directly as unevenness in the finished surface.

No. Sand consolidates unevenly under traffic, so any level made up with extra bedding will settle and dip. Levels are corrected in the compacted sub-base beneath.

Sharp sand, not building sand. It needs to be coarse and free-draining, since fine soft sand holds water and pumps out from under the pavers over time.

Yes, on every free edge. Without it the outer pavers creep outwards under load and the whole field loosens progressively from the perimeter inwards.

A finer kiln-dried sand brushed into the joints after laying, which locks the pavers together. Polymeric versions set slightly and resist weed growth and washout better.

Around 1 in 60 to 1 in 80, sloping away from the building. Flat paving ponds, and the water eventually finds its way under the pavers and into the bedding.

Compacted graded stone, typically 100 mm for a patio and 150 mm or more for a driveway. The bedding sand is a levelling layer, not a structural one.

With a plate compactor over a rubber mat after laying and before jointing, then again after brushing in the jointing sand. Compacting without the mat chips the paver surfaces.

Almost always an inadequately compacted sub-base beneath that spot, or a service trench backfilled without compaction. The bedding sand cannot bridge a soft area.

A white bloom of salts brought to the surface as the pavers dry. It is cosmetic and usually weathers away over months, and washing it off tends to bring more out.

Yes, on a bound bedding rather than loose sand, and the concrete must drain — trapped water beneath a rigid construction has nowhere to go and causes failures in frost.

A block splitter for straight cuts, or a disc cutter for anything shaped. Cut pavers should be no smaller than about a quarter of a paver, or they work loose under traffic.