Estimating and Plan Reading
What is tested
Estimating and plan reading asks you to quantify work from drawings and specifications and to convert units correctly. Expect scale reading, dimension strings, section and elevation interpretation, quantity takeoff, waste, and CSI MasterFormat organization.
Core rules
- Check the scale: architectural scales (1/4 in = 1 ft) differ from civil engineering scales (1 in = 20 ft). Measure in the drawing units, then convert once.
- Takeoff is net quantity plus waste. Order quantity = net × (1 + waste %). Order units must match supplier units (cy, tons, LF, EA).
- Specifications govern quality and submittals; drawings govern size and location. Where documents conflict, follow the contract order of precedence and issue an RFI rather than guessing.
- CSI MasterFormat divisions organize work: 03 Concrete, 05 Metals, 06 Wood, 07 Thermal and Moisture, 08 Openings, 09 Finishes.
- Verify nominal versus actual lumber and nominal pipe sizes.
Worked example
A slab is 30 ft by 40 ft by 6 in. Volume = 30 × 40 × 0.5 ft = 600 ft³. Convert: 600 ÷ 27 = 22.22 yd³. Add 5% waste: 22.22 × 1.05 = 23.33 yd³, so order 23.5 or 24 yd³. Reasoning: 6 in = 0.5 ft, and 27 ft³ = 1 yd³.
Traps
Using the wrong scale; forgetting waste on concrete and masonry; mixing square and cubic units; scaling dimensions from a detail that is not drawn to scale; ignoring specification requirements for testing or submittals.