Patio Build-Up Calculator

Slabs, sub-base, bedding, jointing, edging and excavation for any patio.

Inputs

Got a bay window or conservatory? Set it out in Setting Out & Levels → Bays & conservatories. It carves the bay footprint out of the paved area and adjusts the wall run, then hands the corrected figures back here.

Paving material

Project location

Length(m)

Width(m)

Laying pattern

Slab size

Pick a stock size or choose Custom to enter your own.

Drainage at the house

Pick the drainage detail along the house wall. A shingle strip is the minimum good-practice detail; a dry channel or land drain stops the slabs a course short and adds gravel, geotextile and pipe to the take-off.

19 advanced inputs hidden. Switch to Advanced to fine-tune.

Site context (optional)

Helps tailor algae, weather and longevity advice.

Aspect

Exposure

Confidencehigh· 91Complexitymedium· 42

Slabs required: 36

Based on 600×600mm slabs, 5mm joints, 8% total allowance (5% waste + 3% cuts)

Heads-up: You're on a single-size layout, so every slab is the same dimension. The same material is sold in several sizes (600×600, 900×600, 800×800, 1200×600…). Why it matters: Larger slabs mean fewer pieces but heavier lifts and more cut waste — switch the Slab size above to match what your supplier actually stocks before ordering.

24 detailed breakdowns hidden — switch to Advanced for the full breakdown.

This app provides general UK guidance and material estimates only. It is not legal, planning, engineering or building-control advice. Always confirm requirements with your local planning authority, building control, utility providers, manufacturers or qualified professionals.