Estimating, Plans, and Specifications
This domain tests quantity takeoff, drawing interpretation, specification reading, and bid arithmetic. Questions often require converting units, applying waste factors, reading scales, and recognizing which document governs a detail.
Core rules and concepts
- Architectural drawings show layout, finishes, and dimensions; structural drawings show framing, foundations, and reinforcement. Civil drawings control site grades and utilities. General notes and schedules carry requirements that are easy to miss.
- Specifications are commonly organized by CSI MasterFormat divisions. Division 01 governs submittals, substitutions, quality control, and temporary facilities. A specification requirement can exceed a drawing note.
- Takeoff quantities should be net then adjusted for waste, overlap, and compaction. Concrete is ordered in cubic yards; 27 cubic feet equals one cubic yard. Rebar is estimated by bar length and lap; formwork by contact area.
- Addenda modify bid documents before opening. The estimator must incorporate every addendum and record its effect on scope and price.
Worked example
A 20 ft by 30 ft slab is 4 in thick. Volume = 20 x 30 x (4/12) = 200 cubic feet. Divide by 27 = 7.41 cubic yards. Add 5% waste: 7.41 x 1.05 = 7.78 cubic yards, so order about 7.75 to 8 cubic yards. The reasoning depends on converting inches to feet before multiplying.
Traps that cost marks
Confusing nominal and actual lumber dimensions; ignoring general notes; failing to convert inches to feet; forgetting waste or compaction; using architectural scale on a structural sheet; and missing an addendum that changes the scope.
Key point: the estimator must read drawings, specifications, and addenda together.