RoofRangeBaseFlat roof replacement cost
Flat roof replacement is a membrane job — TPO, EPDM, modified bitumen — not shingle bundles. This page uses the flat installed band (about $500 / $800 / $1,200 per square as of 2026-07) with tear-off on for a typical redo. Mid all-in near $950 per square ($800 + $150 tear-off) is the planning anchor before ponding, insulation recover, and parapet flashing shove real quotes toward high. Low-slope work punishes skipped tear-off when old layers trap moisture. If your bid assumes overlay on a saturated deck, compare a full strip path here before you sign. When the bid names TPO or EPDM specifically, jump to those calculators for tighter product bands.
Runs in your browser No signup Estimate only — not a contractor quote
Tear-off
Remove existing roof before install
Low
$12,000
Mid
$19,000
High
$29,000
When to use — and when not to
When to use
Garage, porch, or low-slope section quoted separately from the pitched shingle field. Comparing membrane bids on a townhouse flat lid. Budgeting a full strip-and-recover on an aging EPDM roof.
When not to
Pitched architectural shingle replacement → asphalt roof replacement cost. Large commercial membrane with insulation recover → commercial roof cost calculator.
Assumptions
Flat material band with tear-off on. Insulation board or tapered crickets are not itemized — raise mid when recovering ISO. Internal drains and parapet rebuild are extras.
Worked examples
12 squares flat mid + tear-off mid
Mid ≈ 12 × ($800 + $150) = $11,400
Small flat sections still carry mobilization — per-square bids can look steep.
12 squares flat high + tear-off high (multi-layer strip)
High ≈ 12 × ($1,200 + $250) = $17,400
Insulation wet-out often expands scope after tear-off.
How it calculates
flat_redo ≈ squares × (flat_$ + tearoff_$) × complexity
Flat redo math: membrane install band plus tear-off on the same low-slope squares.
- Measure the flat field in squares — include attached porch lids if they share the job.
- Keep flat material selected and tear-off on unless a written overlay plan is code-approved.
- Read low / mid / high — mid all-in near $950 per square ($800 + $150) in the 2026-07 table.
- Bump mid/high when insulation recover, crickets for ponding, or long parapet flashing is in scope.
Common traps
- Ponding areas may need tapered insulation — not in default mid.
- Parapet walls and coping metal are frequent extras on flat bids.
- Overlay on trapped moisture fails fast — verify tear-off scope.
- Residential flat and commercial field pricing diverge — see commercial page for larger jobs.
Next tool
Rubber / EPDM focus → rubber roof cost calculator.
TPO membrane → TPO roof cost calculator.
Pitched shingle redo → roof replacement cost.
FAQ
Our 2026-07 flat band runs about $500 / $800 / $1,200 installed per square, plus tear-off about $100 / $150 / $250. Mid all-in near $950 per square is a planning anchor before insulation recover or parapet work pushes higher.