Garden Surveyor logoGarden Surveyor

Patio Build-Up Calculator

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

All calculators
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.

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

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.

Confidencehigh· 91Complexitymedium· 42
Slabs required
36

Order what you need for this job

Ad · Some links are sponsored. We may earn a small commission at no extra cost to you. Suppliers are chosen for fit, not commission.

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.

Drainage & falls

Surface drainage is advised here — set a gentle fall away from the house and any structures.

Lay paving with falls of 1:80 (recommended) or 1:60 (minimum) away from buildings.

Why it matters: Smooth paving needs a positive fall to overcome surface tension and shed water before it ponds in low spots.

If ignored: Insufficient falls cause standing water, algae growth, freeze-thaw damage and water tracking back toward the building.

  • • Recommended falls: 1:80
  • • Falls 1:80 minimum
  • • Surface water must drain to a permeable area or drain

Quantities pre-filled from your calculation (15.0 m²). Partner links — we may earn a small commission if you buy, at no cost to you.

Essentials for this job

Quantities include a ~10% waste allowance. Guide prices are indicative UK ranges (materials only, inc. VAT) — always confirm with the supplier before ordering.

Prefer to hire a pro?

Compare quotes from vetted local trades using this exact spec.

Up to 3 quotes No obligation Free

Ad · Some links are sponsored. We may earn a small commission at no extra cost to you. Suppliers are chosen for fit, not commission.

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.