Estimating, Bidding, and Project Scheduling
Bidding
Bid documents - drawings, specifications, general conditions, and addenda - form the basis of a lump-sum or unit-price bid. Takeoffs are organized by CSI division, and each quantity carries a waste factor (commonly 5–10% for concrete and masonry, more for finish materials). Price is quantity × unit cost, then job overhead, general overhead, profit, contingency, bonds, and insurance are added. Questions test whether you know that addenda issued before bid opening must be acknowledged, that unbalanced bidding (front-loading early items) is a red flag, and that a self-inflicted scope gap is not excused merely because the owner stayed silent.
Scheduling
Critical path method (CPM) finds the longest chain through the network; that chain has zero total float and sets project duration. Total float belongs to the path, not to a single activity, so consuming another activity's float creates a claim. Crashing adds resources to shorten duration at added cost; fast-tracking overlaps phases and adds risk. Resource leveling shifts work within available float and often extends duration. A lag adds time; a lead subtracts it.
Traps
- Adding durations along every path instead of isolating the driving path.
- Forgetting that float is shared and that using it may require notice to the owner.
- Ignoring escalation, bond premiums, and contingency when comparing bids.
Worked example: a 1,200 sf slab at 4 inches thick is 1,200 × 0.333 = 400 cf; 400 ÷ 27 = 14.8 cy. Add 5% waste: 15.6 cy, so order 16 cy.