Project Planning, Estimating, and Contracts
Domain 8 tests commercial judgement: defining scope, measuring quantities, pricing labour and materials correctly, and controlling change through the contract. Expect takeoff arithmetic, markup versus margin, and questions about contract documents.
Scope, takeoff and pricing
Start from a written scope and a scaled plan. Do a quantity takeoff by measurement, then add waste factors - around 5% for pavers and block, 10% for plants and sod, more for cut-heavy patterns. Labour is estimated as crew-hours or crew-days per unit, then multiplied by loaded rates that include burden, insurance and small tools. Overhead and profit are added separately: markup is a percentage of cost, margin is a percentage of price, so a 20% markup gives only a 16.7% margin (0.20 ÷ 1.20). Contract documents typically include the agreement, scope, drawings, specifications, schedule and general conditions. Fixed price suits well-defined work; time and materials suits uncertain work. Every change should be a written change order signed before work proceeds, stating price and schedule impact. Retainage of 5–10% and lien rights protect the parties.
Worked example
A 250 m² paver walkway: 250 × 1.05 = 262.5 m² of pavers. Base at 120 mm depth: 250 × 0.12 = 30 m³ compacted, so order about 20% more loose volume. A crew of three for two days equals 6 crew-days at the loaded rate, plus machine hire, disposal and 15% overhead. Adding 15% profit on total cost gives roughly a 13% margin - check it against the company target before submitting.
Traps that cost marks
Confusing markup with margin. Bidding from memory instead of a takeoff. Verbal changes with no written order. Forgetting disposal, permits, traffic control and restoration.