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Estimating process

Material pricing, waste, and pack sizes.

Materials typically account for 30–40% of a construction project cost. Getting the price, waste allowance, and ordering quantity right is essential for protecting your margin.

Who this guide is for

Estimators pricing materials, buyers placing orders, and site managers managing deliveries and stock.

Sourcing material prices

Get current prices from suppliers for the specific project. Trade accounts typically get better rates than retail. Request quotations for the full project quantity to secure volume discounts. Check prices are valid for the period between estimate and order — material prices can change quickly.

Miniature example

Plasterboard for a 50 m² ceiling: 50 m² ÷ 2.88 m² per board (standard 2400 × 1200 mm) = 17.4 boards. Round up to 18 sheets (pack sizes come in pallets of 50, so order 50 or share with other areas). Add 5% waste: 52.5 m². Unit cost £4.80/sheet. Material cost: 18 sheets × £4.80 = £86.40 before waste.

Common mistakes

• Ordering exactly the measured quantity without waste allowance or pack size rounding
• Using list prices instead of project-specific quotations
• Not checking whether delivery costs are included in the unit price