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Torch-down roofing is modified bitumen: rolls of asphalt sheet heat-welded at the laps. HomeGuide's 2026 guide puts it at $4.00 to $7.50 per square foot installed — APP at $4 to $7 and SBS at $3.50 to $6.50 — with removal of the old roof adding $1.00 to $1.30, and This Old House (June 2026) says most torch-down jobs land at $6 to $8. A 1,000 sq ft APP roof with tear-off is about $5,000 to $8,300. When a roof is stripped to the deck, energy code usually asks for new insulation, and that changes the price more than the membrane: Roof Observations (January 2026) prices a bare 2-ply SBS roof at $9.63 per square foot but the same roof over R-25 to R-30 insulation at $16.13 to $17.23, and a 3-ply system at $19.13 to $20.23. A two-layer system lasts about 15 years and a three-layer one 20 to 25.
Torch-down roofing is modified bitumen: rolls of asphalt sheet heat-welded at the laps, usually a base sheet and a granulated cap sheet. The price depends far more on what is under the membrane than on the membrane itself.
| System | Installed / sq ft | 500 sq ft | 1,000 sq ft | Typical life |
|---|---|---|---|---|
| APP modified bitumen (torch-applied) | $4.00 – $7.00 | $2,000 – $3,500 | $4,000 – $7,000 | 15–20 years |
| SBS modified bitumen | $3.50 – $6.50 | $1,750 – $3,250 | $3,500 – $6,500 | 15–20 years |
| SBS 2-ply over new R-25 to R-30 insulation | $16.13 – $17.23 | $8,065 – $8,615 | $16,130 – $17,230 | 15–20 years |
| SBS 3-ply over new R-25 to R-30 insulation | $19.13 – $20.23 | $9,565 – $10,115 | $19,130 – $20,230 | 20–25 years |
APP and SBS bands and old-roof removal ($1.00–$1.30 per sq ft) from HomeGuide's 2026 modified bitumen guide; insulated systems from Roof Observations (January 2026), which prices a bare 2-ply SBS roof at $9.63 and a bare 3-ply at $12.63 per sq ft. This Old House (June 2026) says most torch-down jobs land at $6–$8 and repairs at $2.50–$8.50 per sq ft.
HomeGuide (2026) puts modified bitumen at $4.00–$7.50 per sq ft installed: APP $4–$7 and SBS $3.50–$6.50. This Old House (June 2026) says most torch-down jobs land at $6–$8. Removing the old roof adds about $1.00–$1.30 per sq ft.
About $3,500–$7,000 for the membrane alone, plus $1,000–$1,300 for tear-off. If the deck is stripped and new insulation is needed to meet energy code, a 2-ply SBS system with R-25 to R-30 board runs about $16,000–$17,000 (Roof Observations, 2026).
This Old House gives about 15 years for a two-layer system and 20–25 years for three layers. Our lifespan table uses 15–20 years for modified bitumen. Good drainage matters more than the brand: ponding water shortens it.
APP is plastic-modified and handles heat and UV well; SBS is rubber-modified, stays flexible in cold weather and can be torched, mopped or self-adhered. Both are proven; the right one depends on climate and how the roofer installs.
It uses an open flame, so many roofers use self-adhered SBS near wood, skylights and walls, and some insurers and cities restrict torching. Ask how the roofer will handle fire watch and the details near combustible edges.
Comparing single-ply membranes? The TPO and EPDM roof cost calculator prices them with insulation and tear-off.
Need the whole roof at once? The free roofing calculator works out roof area, squares, shingle bundles, underlayment, drip edge, ridge cap and installed cost from one set of measurements.