Patio Area Calculator

Area = length × width (an L-shape uses the fill fraction of its bounding rectangle). Slabs = ceil(area ÷ slab footprint × wastage); a 600×600 mm slab with a 10 mm joint covers 0.37 m², so about 2.7 slabs per m². Sub-base is MOT Type 1 at 100 mm compacted depth (~2.0 t/m³); bedding mortar is a 40 mm full bed.

Yes. The default 10% allowance covers cuts, breakages and spillage for sandstone or concrete slabs — increase it to about 15% for porcelain or for a patio with many angled cuts.

For a foot-traffic garden patio, lay 100 mm of compacted MOT Type 1 (this calculator assumes 100 mm). A driveway or load-bearing surface needs 150 mm or more.

Allow 3-4 m² per person for comfortable dining. A family of four needs about 12-16 m². Standard sizes are 3×3 m, 4×3 m, or 4×4 m.

Yes, a minimum fall of 1:80 (12.5 mm per metre) away from the house is essential. This ensures rainwater drains away and does not pool against walls.