A roofing bid looks self-contained in a way most trades don't: the plan shows the assembly, the details show the flashing conditions, the field prices cleanly from a takeoff. Every curb, drain, parapet and penetration is a place where roofing's scope touches somebody else's — and the attachment requirements that decide how much fastener and adhesive the field actually needs are frequently a wind-engineering exhibit sitting apart from the roof plan entirely.
The field of the roof is the easy part
- Membrane roofing system complete — the specified assembly bottom-up: vapour retarder, insulation and tapered packages, cover board, membrane and surfacing, per roof area and detail. Confirm who designs the tapered layout and the minimum R-value required at drains; both change the insulation takeoff independent of the membrane spec.
- Base and cap flashings — membrane flashing at every upstand, curb and penetration, plus metal counter-flashings and copings wherever assigned to this scope rather than cladding. This is where roofing labour concentrates; the field membrane rolls out fast, the flashing details don't.
- Roof specialties and accessories — walkway pads, pitch pockets, breather vents, gum boxes: a per-each list the roof plan scatters across dozens of small callouts rather than gathering into one schedule, which is exactly why it's easy to under-count.
- Manufacturer warranty — the term and type demanded, with its inspection and approved-applicator conditions. A 20-year NDL warranty with mandatory manufacturer inspections costs differently than a materials-only warranty, and the tender rarely states that difference in dollars.
The edges: three boundaries that look like yours and are only half yours
Drains. The drain body is plumbing's, supplied and set by that trade. Flashing into it — the membrane detail that actually keeps water out — is roofing's. Extract both halves separately; it's common for each trade to assume the other carries the whole assembly.
Curbs. Curb construction is rough carpentry's or mechanical's supply, not roofing's. Extract the sizes anyway: every curb on the roof plan is flashing labour for you regardless of who built the box underneath it, so the curb schedule matters to your takeoff even though the curb itself isn't your line item.
Skylights and hatches. The units are frequently supplied by others where the documents assign them that way, with curb flashing and integration staying in roofing scope. "Supply by others" doesn't mean "no roofing cost" — the flashing and integration labour is often the larger number anyway.
Three disputes that repeat on almost every tender
Metal roofing, split from the membrane package or not. Standing-seam or profiled metal shows up as a distinct roof area — a canopy, an entry feature, a mechanical penthouse — and specs handle ownership inconsistently: sometimes priced with the membrane trade as one package, sometimes a dedicated sub carrying its own system and warranty. Extract which this tender is; don't assume from the last job that looked similar.
Temporary roofing and phased cutoffs. Additions, partial reroofs, sequenced areas on an occupied building usually need temporary membranes and night seals to keep water out between work sessions — real labour and material a straight roof-area takeoff won't show, since it's driven by the construction schedule, not the roof plan. More than a handful of cutoffs in the phasing plan means pricing the cutoffs themselves, not just the finished area.
Fall-arrest anchors. These carry an engineering and certification duty separate from the physical install, and the split isn't consistent across tenders — sometimes a specialty fall-protection vendor engineers and supplies while roofing installs and flashes, sometimes roofing carries the whole package including certification. A certified system with engineering sign-off costs differently than a stock anchor bolted through the deck; confirm which before treating the anchor line as a minor accessory.
Three documents that aren't the roof plan, and aren't optional
- The wind engineering exhibit. FM or RC-4 style uplift ratings, with enhanced attachment at perimeters and corners, live here or in a general note rather than on the roof plan — and attachment density is what prices the field, not just the membrane spec. A perimeter zone with double the fastener count changes labour across the whole edge condition, not just at the corners.
- Existing-conditions language, on a reroof. Core cuts, wet-insulation allowances, deck condition language and unit rates for deck or insulation replacement are the difference between a clean tear-off and a job that opens up unknowns the moment the membrane comes off. No stated unit rate for replacement is the finding to flag before pricing a lump sum against an assumption.
- Whatever governs protection during construction. Other trades working over a finished roof — mechanical setting rooftop units, cladding building parapets — need protection in place, and damage responsibility needs an owner. Usually a Division 01-adjacent coordination item rather than a roofing-section line, easy to miss because it only becomes a cost once someone else's trade is actually up there.
Who you're sharing the roof with
| Trade | What to reconcile before you price |
|---|---|
| Mechanical | Curb sizes and locations, equipment set sequence after membrane is in, and the full penetration schedule before flashing quantities are final. |
| Plumbing | Drain locations and sump details — confirm the drain body and the flashing-in are priced by the correct trade on each side of the split. |
| Cladding | Parapet and roof-to-wall transitions, and coping ownership specifically — a detail that gets drawn once and claimed by neither trade if nobody checks. |
| General contractor | Staging, phasing cutoffs, and protection of completed roof areas once other trades are working above them. |
The assembly is the easy part of a roofing bid. The edges, and the sheets they're documented on, are where the number holds or doesn't.