Last reviewed October 31, 2026.
The brown ring is back on the ceiling under the back addition, in the same spot that got patched two summers ago. This time the roofer is talking about a whole new roof, not another repair. On a small flat roof, square footage barely moves the price. Everything around the membrane does.
How EPDM, TPO and modified bitumen differ, and what County Roofing Systems and Greene Group charge for them, is on our flat roof page. Patches, seams and blisters are priced in the roof repair cost guide. This page rounds up the other Long Island roofers who publish replacement prices for houses.
Residential flat roof prices, company by company
| Company | What the price covers | Published price |
|---|---|---|
| LI Roofing Co. (2026) | Flat or TPO roof, 2,000 sq ft | $8,000 to $18,000, or $4 to $9 per sq ft |
| Ready Roof (May 2026) | Quality single-ply systems | about $8 to $16 per sq ft |
| Ready Roof (May 2026) | Residential flat roof, 500 to 1,500 sq ft | about $5,000 to $20,000 |
| All American Home Improvement | Home of 1,000 to 1,500 sq ft | $5,000 for EPDM up to $11,250 for TPO or PVC |
| All American Home Improvement | Home of 1,500 to 2,500 sq ft | $7,500 to $12,500 EPDM, $11,250 to $18,750 TPO or PVC |
| All American Home Improvement | Over 2,500 sq ft | EPDM from $12,500, TPO or PVC to $30,000 or more |
The two square foot ranges overlap only between $8 and $9. Before comparing them, ask each roofer what its number includes. Ready Roof says its price moves with roof size, insulation, tear-off needs, membrane type and the condition of the substrate underneath. All American frames its tiers by home size rather than roof area. RoofVista’s island-wide flat membrane estimate sits with the other materials in our roof replacement cost guide.
EPDM, TPO and modified bitumen side by side
Expressway Roofing & Chimney in Manorville is the one residential roofer we found that breaks its replacement price out by membrane:
| Membrane | Installed, per sq ft |
|---|---|
| EPDM | $4 to $9 |
| TPO | $5 to $10 |
| Modified bitumen | $4 to $8 |
Expressway says those prices include removing the existing materials, new insulation if needed and proper flashing. All American lands in the same order, with EPDM at the bottom of every size tier and TPO or PVC at the top. Roofing Time Inc. in Bellport rates EPDM and modified bitumen as mid-range and TPO as higher in its own comparison chart, without dollar figures. We found no Long Island company publishing a separate residential price for PVC. What the thickness and seam choices mean for a rubber roof is on our EPDM page.
Tear-off and extra layers
All American Home Improvement lists removal of the old roofing as an added $1,000 to $5,000 or more. LI Roofing Co. adds $1,500 to $3,500 when several roof layers have to come off, listed among the general factors that move any quote rather than under its flat roof price. Expressway already folds removal into its square foot price, so set its number against another company’s all-in total, not a base membrane price.
Insulation rules when a house flat roof is replaced
New York’s 2025 Energy Conservation Construction Code reaches houses too. Section R503.1.1.2 says that when a roof assembly with insulation entirely above the deck is replaced, or its covering is removed and replaced, the insulation has to meet the current requirements. Table R402.1.3 sets that at R-30 continuous insulation in climate zone 4, the zone the code lists Nassau and Suffolk under. Section R503.1.1 exempts a roof recover, a new covering laid over the old one, as long as the home’s energy use does not go up.
Find out whether your roof has board insulation above the deck. If it does, check that the quote includes enough to reach R-30. North Shore Roofing in Port Washington says insulation can make up 25 to 40 percent of a project’s total cost, though its July 2026 guide is written for commercial buildings. The commercial version of the code rule is on our commercial roofing page.
Drains, decking and soft spots under the membrane
Rotted plywood cannot be priced until the old roof is off. Roofing Time Inc. puts the stakes plainly, writing that it is “not interested in laying a brand-new $15,000 rubber roof over punky OSB.” County Roofing’s price range for rotted deck repairs is on the flat roof page. Get the per-sheet price for replacement decking in the contract before the crew pulls up the first piece.
The drain is the other unknown. Ready Roof’s price for a drain or penetration repair is in the roof repair cost guide, but we found no Long Island roofer we could verify publishing a price to replace a drain or add a scupper on a house. If water stands near the drain, ask for that work as its own line on the quote.
Coating instead of replacing
A coating can push a replacement back a few years on a roof that is still dry underneath. The one residential coating price we found from a Long Island company, and the cases where a coating seals in a problem, are on our roof coating page. For comparison only, North Shore Roofing lists restoration coatings at $4 to $9 a square foot in its commercial guide, and All American lists roof coating and waterproofing on commercial roofs at $2,000 to $7,500. Neither figure is for a house.
Lining up two flat roof quotes
Lay the quotes next to each other and make sure each one names:
- the membrane, its thickness, and whether it is glued, fastened or torched down
- the measured square footage, so the per foot price can be checked
- whether removal is included and how many layers the roofer expects
- the insulation, by R-value, if any goes on
- a per-sheet price for rotted decking
- drain, scupper and wall flashing work as separate items
- who stands behind the roof, the manufacturer or only the company
When one total comes in far below the rest, look first for missing removal or decking.
