Chapter 12 — Key Takeaways

One-page reference card. Estimating fundamentals: takeoffs, unit costs, and building a bid.

Key Takeaways

  • An estimate is not a prediction. It is a priced bundle of assumptions, quantities, and risks — and every one of them belongs to somebody. Your product is not the number; it is the documented set of decisions the number rests on.

  • The estimate has three layers: direct costs (labor, material, equipment, subcontracts), indirect costs (general requirements from Division 01, plus general conditions — your team and its infrastructure), and markups (escalation, insurance, bond, contingency, overhead, profit, taxes). Everything above the direct-cost line is a percentage of a number somebody measured off a drawing.

  • A 1% takeoff error consumes about 22% of the profit on Northgate. $400,000 against a $1,804,800 fee. The leverage runs the wrong way and it always will.

  • Formwork quantity has almost nothing to do with concrete quantity. Formwork is surface geometry — length × height × faces. Thickness does not appear in the formula. Identical 37 CY elements can need 233 SFCA or 2,000 SFCA.

  • Dirt exists in three states. Bank (in the ground), loose (in the truck), compacted (in place). Swell takes you bank→loose; shrinkage takes you bank→compacted. A quantity without a stated measure is not a quantity — and extending 32,000 BCY at a loose-measure haul rate is a $148,000 mistake.

  • Waste goes in exactly one place. The quantity or the price, never both. Waste is a material factor, not a labor factor; your crew does not install the waste.

  • Digital takeoff changes the speed, not the assumptions. It cannot tell you an item is on a sheet you did not open, cannot decide a scope boundary, and will happily report false precision. Model-extracted quantities are only as good as the model's level of development.

  • The unit cost formula works on anything: unit cost = (crew cost/hr ÷ production/hr) + material/unit + equipment/unit. Labor and equipment are time-based; material is quantity-based. The production rate is the exchange rate between the two.

  • The wage is not the cost. A $34.00 carpenter burdens to $50.47 — a 1.484 factor — through fringes, payroll taxes, workers' comp (by class code, adjusted by your EMR), general liability, and small tools. The same laborer costs a different amount in a framing crew than in a trench crew.

  • Your own historical data beats anyone's book. Published cost data is a starting point and a sanity check, not a basis for self-performed work. The cost report is what generates next year's estimate.

  • Markup is not margin. A 10% markup is a 9.09% margin. For a 10% margin you must mark up 11.11%. markup = margin ÷ (1 − margin) and margin = markup ÷ (1 + markup).

  • Sustained overtime buys time, not productivity. A 6×10 schedule costs 70% more per week to gain 26% more output — about $11.98 per additional unit against a $4.43 baseline. And it raises incident rates, which is a cost that never appears in the arithmetic.

  • A qualified bid states its exclusions where a reader will find them. A hidden-exclusion bid buries them. The test: would the owner, reading this for five minutes, know what they are not buying?

Action Items — what to do on your job this week

  1. Open your last takeoff. Does every quantity cite a sheet and a detail? If not, fix one scope today and adopt the habit permanently.
  2. Get your real burdened rates from accounting — current fringe contributions, current payroll tax effective rates, current workers' comp manual rates by class code, and your company's EMR. Build one classification from scratch. Most estimators are using rates two years stale.
  3. Reconcile a count against a schedule total on something you are working on right now. It takes thirty seconds and it is the check that would have caught Dani's nine footings.
  4. Find one production rate in your estimate and write its basis next to it — where it came from and what conditions it assumes. Then ask your superintendent whether those conditions exist on this job.
  5. Check your last bid for markup-versus-margin. Compute the margin you actually earned. If it is lower than the number you told your executive, you know why now.
  6. Write a one-page basis of estimate for your current scope, using the six sections. If it takes more than ninety minutes, your estimate has more undocumented decisions in it than you thought.
  7. Read the last page of every subcontractor quote in your file. That is where the exclusions live.

Common Mistakes — and the fix

Mistake What it looks like The fix
Completeness error — measuring only the sheet in front of you Plan count 139, schedule total 148 Reconcile counts against schedules; maintain a sheet index and tick every sheet
Reading error — line-skip on a wide schedule F-6 carried at F-5's thickness A physical control: straightedge on paper, highlighted row on screen, read-back by a second person
Conceptual error — pricing geometry instead of material A takeoff total with no waste line A takeoff template with a mandatory waste line that cannot be left blank
Double-counted waste Waste in the quantity and in the unit price Written company policy: waste lives in the quantity, full stop
Unit conversion BCY extended at an LCY rate; SF ÷ 3 instead of ÷ 9; ton vs. tonne; CWT vs. TON Write the unit next to every number; state bank/loose/compacted on every earthwork line
Stale or borrowed productivity rate A warehouse rate applied to an occupied hospital corridor Write the rate's basis and conditions beside it, every time
Unread quote exclusions "Excludes unloading, hoisting, and layout" on page two Scope sheets and a scope-corrected bid tab, not a face-value comparison
No independent number for subcontracted trades A low bid you cannot evaluate Build a defensible order-of-magnitude number for every major trade
Escalation forgotten A 14-month buy window priced at bid-day prices Log every quote's validity date; escalate the late-buy scope only
The cost of time forgotten Duration grows, general conditions do not Re-run GC every time the schedule changes; keep the CPM open while you estimate
Markup taken for margin "We're at ten points" — you are at 9.09 Memorize both conversion formulas; state which one you mean, every time
Bond computed on the pre-bond subtotal Under-bonded by ~$1,200 on $6.8M Use the divisor method: Price = Subtotal ÷ (1 − rate)
False precision from a tool "18,614.37 LF" carried as gospel Round extracted quantities to the precision you can defend before they enter the estimate
Assumptions that live in your head Everything above, eventually The basis of estimate. Six sections. Every job.

Decision Framework — pricing a scope you have never priced

Step Ask If you cannot answer
1 What unit is this work bought in? Look at how a subcontractor would quote it
2 Where is the quantity? Where is the quality? Drawings govern quantity and location; specifications govern quality and product
3 Have I measured it twice, by two different methods? You have one number and no check
4 Self-perform or subcontract? Either way, build an independent number
5 What crew does this, and what does it cost burdened? Ask accounting for current rates and the correct class code
6 What does that crew install in a day, under what conditions? Historical data first, published second, foreman third
7 What material, plus waste, plus freight, plus tax? Get a quote and log its validity date
8 What equipment, for how many days, including idle and mobilization? Open the schedule
9 What did I assume, and who owns it if I am wrong? This is the estimate. Write it down.

The Numbers Worth Memorizing

   CY from area:      CY = SF × (inches ÷ 12) ÷ 27
   Unit cost:         UC = (crew $/hr ÷ production/hr) + material/unit + equipment/unit
   Markup ↔ margin:   markup = margin ÷ (1 − margin)
                      margin = markup ÷ (1 + markup)
   Circular rate:     Price = Subtotal ÷ (1 − rate)        [bond, gross-receipts tax]
   Swell:             LCY = BCY × (1 + swell)
   Shrinkage:         CCY = BCY × (1 − shrinkage)
   Formwork:          SFCA = length × height × faces       [thickness does not appear]

Northgate quick-reference: 132,000 SF · GMP $47,500,000 · $360/SF · GC burn $5,150/CD · LDs $5,500/CD · total daily exposure $10,650/CD · fee $1,804,800 (4.0% markup = 3.80% margin) · 44,000 CY cut / 12,000 CY fill / 32,000 CY net export · 148 footings, 1,240 CY · 620 CY walls and grade beams · 33,000 SF slab at 5" = 510 CY · 985 tons steel · 99,000 SF deck · 18,600 LF partitions · 412,000 SF gypsum board · 412,000 total craft man-hours.

Next: Chapter 13 — Detailed Estimating, where this takeoff becomes a complete priced bid organized by CSI division.