On a Phoenix flat roof, "replacement" is usually the wrong word. Most flat roofs here are foam, and a foam roof is recoated ($2–$4/sq ft) or re-foamed over the old roof ($3.50–$9) long before it is torn off ($10–$15). Here is what each costs, and how to tell which one you need.
| Job | Published Valley rate | On a 2,000 sq ft roof | When it is the right call |
|---|---|---|---|
| Recoat (clean, prime, new elastomeric or silicone top coat) | $2–$4 / sq ft | $4,000–$8,000 | Foam is dry; coating chalked or thin. The normal 5–7 year job. |
| Spray foam over the existing flat roof | $3.50–$9 / sq ft | $7,000–$18,000 | Built-up, modified bitumen or old foam that is sound but past coating; adds slope and R-6.5/in. |
| Tear-off and new flat roof (foam) | $10–$15 / sq ft | $20,000–$30,000 | Wet foam throughout, rotted deck, or a roof that has carried three systems already. |
| TPO single-ply, new | $6–$10 / sq ft [est.] | $12,000–$20,000 | Commercial roofs with heavy foot traffic or mechanical penetrations; rare on homes here. |
Sources: Travek (recoat $2–$4, replacement $10–$15), Arizona Roof Co ($3.50–$7 new foam), Durafoam ($5–$9 new foam). TPO band is an estimate from commercial quotes, not a published residential rate. Compiled 2026-11-01.
Drag to your roof size. The bands are the published per-square-foot rates above, not our pricing.
Tip: a typical single-story Phoenix flat roof is 1,600–2,400 sq ft. Measure the footprint on the Maricopa County Assessor parcel map and add 5% for parapets.
Before any of the above, most calls are a repair. Flat roof repair cost on a foam roof runs from a few hundred dollars for pinholes and bird-peck holes to $1,000–$2,500 for a saturated section cut out and refoamed. The full table with times is on the repair page; the 48-hour ponding rule decides whether a low spot is a repair or a tapered-foam fix.
Residential flat roofing in the Valley is foam for three reasons: it is sprayed seamless over the old roof (no tear-off cost), it builds slope to the scuppers (the cure for ponding), and it insulates at R-6.5–7 per inch, which shows up on a July APS or SRP bill — see the cooling calculator. The comparison with tile and shingle, and with a pitched conversion, is on foam vs tile vs shingle and flat vs pitched.
$10–$15 per square foot for a tear-off and new foam roof — $20,000–$30,000 on a typical 2,000 sq ft home — but most Phoenix flat roofs are re-foamed over the old roof for $3.50–$9 per square foot or simply recoated for $2–$4. A roofer who quotes a tear-off first should show you the wet core samples that justify it.
A recoat, if the foam underneath is dry: $2–$4 per square foot renews the top coat and resets the clock for 5–7 years. Spot repairs for pinholes and blisters cost a few hundred dollars each.
A new foam roof, recoated on schedule, lasts 25 years and more. TPO runs 15–20 years and modified bitumen 12–15 in Phoenix sun. See lifespan.
Usually only for sudden damage — hail, wind-lifted edges, a fallen limb — and not for a coating that wore out. After a storm, photograph the roof before any work and ask the roofer for a written cause-of-damage note.
LAST REVIEWED 2026-11-01 · Prices on this site are published Valley rates and estimates, not a quote.