Roof areas by assembly
Measure each roof system separately and use the appropriate slope basis. Identify tapered insulation, cover board or tear-off layers where the roof detail differs from the field assembly.
Roofing and sheet-metal accessories
Roofing Estimating Services
A roofing takeoff separates field coverage from roof edges and penetrations. Measure roof areas by system, then list flashings, perimeter metal, curbs and roof drainage accessories separately.
Roof area alone misses the details that drive labor. We separate roof systems by slope and deck condition and track tear-off, edge metal, penetrations, drains and transitions as their own scope items.
Confirm slope and existing tear-off layers when the drawings identify them.
What this service covers
Perimeters and penetrations
Measure edge metal, parapet flashing and expansion joints by length. Count curbs, drains, scuppers and penetrations separately because these details rarely scale with roof area.
Replacement scope
Confirm which layers are removed and what stays. Record any allowance for substrate repairs, staged tear-off or temporary protection before using the quantity for a reroof bid.
A roofing bid is not a price per square. The field — the open, flat middle of the roof — is the cheapest part of the job and the easiest to measure. Everything that costs money lives at the edges: the parapet where the membrane turns up, the curb where a unit sits, the drain where the water leaves, the penetration where a pipe comes through. Two roofs with the same field area can differ sharply in price, and the difference is all in the details the field measurement never sees.
That is why this estimate starts at the perimeter and works inward. The roof is measured as a system: field area, then edges, then penetrations, then drainage — each on its own line, each tied to the drawing or the roof plan that shows it. A bidder who can see the edge quantity can price the flashing; a bidder who only sees the field area has to guess it.
What the scope can include
- Roof area by system and slope
- Perimeters, edges and flashings
- Penetrations and curbs
- Insulation and drainage components
- Tear-off and disposal of the existing roof, shown separately from new work
- Deck repair and replacement, where the drawings or survey call for it
- Crickets, saddles and tapered insulation for drainage
- Walkway pads, fall protection and roof access, where specified
Field area is the cheapest number on the roof
Two roofs with the same field area can have very different edge and penetration quantities. Separate base flashings, curb treatments and termination details from roof squares.
Count the edges first. A square roof has four edges; a roof with setbacks, clerestories and a dozen curbs has ten times the flashing length of a plain rectangle the same size. Each edge is a length of membrane turned up, a termination bar, and a flashing detail — and each penetration is a curb, a flashing and a seal that has to be watertight from the first rain. None of that shows up in the field area.
Tear-off first: what comes off before anything goes on
A re-roof is two jobs, and they should never share a number. The first job is taking the old roof off: how many layers, what system, how it is fastened, and where the debris goes. A single layer of membrane over insulation comes off differently from three layers of built-up roofing over a wet deck — and a deck that is wet underneath cannot be priced until someone has seen it.
That is why the tear-off is shown on its own lines, with the survey photographs next to it where they exist. A deck that is wet underneath cannot be priced until someone has seen it, so a roof that has not been cored or walked carries that as an open point rather than pricing the deck as if it were sound.
Edges, penetrations and flashings are the real bid
Walk the roof on paper, edge by edge. The parapet gets base flashing turned up and terminated; the wall gets counterflashing; the expansion joint gets a cover that moves with the building. Each of these is a length, a detail and a material — and each appears on the roof plan, the elevations or the detail sheets, sometimes on all three with different dimensions.
Slope, drainage and the low spot nobody walks
Water does not care about the field area; it cares about the low spots. The estimate follows the drainage the way the roof plan shows it: drains and scuppers by count, crickets behind the curbs that block the flow, tapered insulation where the deck is flat. A roof that ponds is a roof whose drainage was priced as an afterthought.
Insulation is shown the same way — by thickness and by layer, not as a single lump. Two layers with staggered joints are a different scope from one thick layer, and tapered insulation is measured by its average thickness and coverage.
What to send with your plans
Send the roof plan, assembly specifications, elevations, penetration layout and survey photographs for tear-offs.
- The roof plan, with areas, slopes, drains, scuppers and every penetration marked
- Assembly specifications for the membrane, insulation and flashing system
- Elevations and parapet details, with heights and termination conditions
- The penetration layout, with curb sizes and any equipment arriving later
- Survey photographs and core or moisture survey results, for tear-offs
- Whether the bid is for a new roof, a tear-off and replacement, or a recover over the existing system
Frequently asked questions
Do you include waste in the measured area?
The base takeoff shows measured area. Carry waste, overlaps and order quantities as separate assumptions tied to the chosen system.
Do you account for laps and waste?
Show the measured roof area first. Material order factors can be carried separately where the roofing system or manufacturer’s requirements establish them.
How is a tear-off priced against a new roof?
As two separate jobs. The tear-off is shown by layer and by area, with disposal on its own line, and the new roof is measured from the deck up. A deck that the survey could not confirm is written down as an open point, not priced as if it were sound.
What about a roof that ponds?
Ponding is a drainage scope, not a field-area problem. Drains, scuppers, crickets and tapered insulation are measured where the plan shows them, so the low spots are priced as their own work instead of being hidden in the membrane area.
How are penetrations added after the bid handled?
Each penetration is its own line — curb, flashing and seal — so one added later is priced as a single line. The field area does not change, and the rest of the roof does not need to be re-measured.
Is a curb for equipment that hasn’t arrived yet priced the same?
No. A curb for a unit on site is measured from the unit’s dimensions; a curb for a unit arriving later is measured from the curb detail on the drawings, with the unit’s size recorded as an assumption so the curb can be checked when the equipment arrives.
Do you separate the membrane from the insulation?
Yes. The membrane, the insulation by thickness and layer, and the cover board are each their own lines, because they come from different suppliers and are installed in different passes.
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What the estimate can show
- Scope and quantity detail arranged by the trade, system, phase or bid item.
- Document references so scope questions can be traced to the applicable plans or specifications.
- Assumptions and exclusions kept visible, with separate pricing or allowances when requested.
Have a bid set ready?
Tell us what you need priced, which drawings govern the bid and when it is due.