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How to price a TPO roof
A complete walkthrough, from reading the plan set to the number you hand the GC. Written for people who actually do this, so it includes the parts that go wrong.
Start with what the spec says, not what you assume
Before any measuring, find Division 7 and read it. You are looking for six things that set the entire assembly:
- Membrane type and thickness. 60 mil is the commercial default. 45 mil shows up on budget jobs, 80 mil on high-traffic or extended-warranty work.
- Attachment method. Mechanically attached, fully adhered, or induction welded. This changes both material and labor more than any other single decision.
- Insulation and R-value. Which drives layer count, which drives fastener length.
- Coverboard. Required or not, and what kind.
- Warranty term and type. A 20-year NDL is a different bid than a 20-year material-only.
- Deck type. Usually confirmed on the structural sheets, not in the spec.
The takeoff, in the order that avoids mistakes
Field area
Get it from printed dimension strings wherever they exist. Scaling is a fallback, not a method. Break the roof into sections if levels or systems differ, because a single blended area hides a lot of money.
Perimeter and heights
Perimeter comes off the plan. Heights do not. Parapet and wall heights live on the elevations and sections, and this is where estimators lose the most money: they assume a parapet height, price base flashing to it, and find out in the field it was four feet taller for half the run.
Drainage
Count drains, overflows, scuppers, and gutters. Then reconcile against the plumbing sheets, because interior drains appear on both and the counts do not always agree. A roof with zero interior drains and a perimeter gutter is a finding worth writing down, not an absence to skip past.
Penetrations and curbs
VTRs, gas lines, conduit, equipment curbs. Mechanical and plumbing sheets, not the roof plan. Count what the tags say. A heat pump tagged HP-1 is not an RTU, and pricing it as one is a real error.
Material, in the units you actually buy
The bridge from quantity to cost is the coverage rate, and this is where sloppy math compounds:
| Item | How it converts | Watch for |
|---|---|---|
| Membrane | Roll coverage, minus seam overlap | Waste factor differs by roof complexity, not a flat 10% |
| Insulation | Boards per square by thickness | Multiple layers mean staggered joints and more boards |
| Fasteners and plates | Pattern per square by wind zone | Perimeter and corner zones are denser than field |
| Adhesive | Coverage per unit by substrate | Porous substrates drink more than the data sheet says |
| Bonding adhesive | Coverage per unit, two surfaces | Both sides get coated, so it is half the stated rate |
Fastener length is derived, not chosen
The fastener has to reach through the full insulation stack plus the required embedment into the deck. So the fastener length follows the stack thickness, which follows the R-value, which follows the spec. Change the insulation and the fastener line changes with it. And if the job has taper, the average stack thickness changes across the roof, which means the fastener schedule and the freight both move.
Labor, from production rates you can defend
The single most common error in roofing labor is confusing crew-day rates with man-day rates. If your notes say "we do 20 squares a day" with a six-man crew, that is roughly 3.3 squares per man-day, not 20. Price it as 20 per man-day and your labor is off by a factor of six.
Build labor from three inputs:
- Production rate in squares per man-day for the specific system and condition. Tear-off is slower than recover. Adhered is slower than mechanically attached.
- Crew size and burdened hourly rate. Burdened, meaning wages plus taxes, insurance, and workers' comp, which in roofing is not a rounding error.
- Flashing and detail labor separately, usually in linear feet per man-day, because a roof with 40 penetrations and 900 feet of parapet is not the same job as an open field of equal area.
The lines people forget
- Equipment. A telehandler is on essentially every commercial job, for the full duration. Crane days for setting units. Manlifts for wall work.
- Dumpsters and disposal. Tear-off weight varies enormously by existing assembly. A wet ballasted system is a very different disposal number than a single-ply recover.
- Supervision. Weeks on site times the rate.
- Freight. Insulation ships by volume and eats trucks fast. Taper changes truck count.
- Warranty fee. Manufacturers charge for NDL warranties, banded by job size, and the spread between small and large jobs is wide.
- Sales tax by delivery address, not by your office address.
- Permits, bonds, and GC portal fees if the project has them.
Markup, and why the split matters
Overhead and profit are not one number. Overhead covers what it costs to keep the doors open, and it applies to your direct costs. Profit is what the risk is worth. Blending them into one percentage is fine on simple jobs and dangerous when subcontracted work is involved.
Here is why: if a job includes $40,000 of subcontracted taper and you apply a full blended markup to it, you have priced your own risk on money that passes straight through. Competitors who break it out will beat you on that line every time. Carry sub costs separately with their own markup.
Before you send it
- Verify the counts against the roof plan one more time. Counting is where machines and humans both slip.
- Confirm every assumption is written down and visible on the proposal, not just in your head.
- Check that nothing came through at zero. A zero is either a real documented zero with a reason, or a missing price pretending to be free.
- Read the exclusions out loud. If a line is ambiguous to you, it will be ambiguous to the GC in six months.
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