Modified Bitumen (Torch-Down & Cold-Applied) Roofing in NYC
Modified bitumen is a multi-layer, asphalt-based roofing system that has protected flat roofs in New York for decades. It can be applied with a torch or with cold adhesive. East NYC Roofing, in business 20 years, installs and repairs modified bitumen roofs on rowhouses, apartment buildings and commercial properties across the five boroughs, Nassau and Westchester.
- 20 years in business
- 10-year warranty on replacements
- Within 2 hours for leaks
- Free written estimate
Problems this solves
- Cracked or split built-up roof with exposed felt
- Flat roof leaks at seams, edges and flashings
- Granules wearing off the surface and exposing the membrane
- Blisters, ridges or wrinkles in the roof surface
- Water entering at parapet walls or roof edges
- Leaks around drains, pipes and vents
- Patches layered on patches over many years
- Poor performance in cold weather or heavy snow cycles
- Need for a tougher surface where service crews walk the roof
Modified Bitumen Roofing explained
Modified bitumen (often called mod bit) is asphalt blended with polymers for added flexibility and strength, reinforced and supplied as rolled sheets. Roofers layer these sheets, typically a base ply and a granulated cap sheet, to form a redundant, multi-ply waterproofing system. Sheets can be torch-applied with an open flame, cold-applied with adhesive, or self-adhered with a peel-and-stick backing. Mod bit is widely used on NYC flat roofs because it handles foot traffic well and can be repaired in sections. It is a good match for rowhouses, multi-family buildings and commercial roofs with many penetrations.
Options and materials
Torch-down application
Sheets are heated so the underside bonds to the layer below. Strong, well-proven bonds, but open-flame work requires strict fire-safety procedures and qualified crews.
Cold-applied (adhesive)
Plies are bonded with roofing adhesive rather than flame. A good option near combustible materials or where flame work is restricted or undesirable.
Self-adhered sheets
Peel-and-stick sheets bond without flame or liquid adhesive, useful for flashing details, smaller roofs and tight rooftop conditions.
Granulated cap sheet
A mineral-surfaced top layer protects the asphalt from sun and wear. Lighter or reflective surfacing can be chosen to reduce heat.
Mod bit repair and re-flash
Cutting out failed areas and replacing plies, flashings and seams where the rest of the roof still has service life left.
Our process
- Inspection and testingWe examine plies, seams and flashings and check for trapped moisture so the scope matches the real condition of the roof.
- Estimate and approvalsA free written estimate explains the system and application method. We note permit needs and any restrictions on open-flame work at your building.
- Tear-off and deck prepFailed roofing is removed, damaged deck is repaired, and surrounding areas are protected before new materials go down.
- Insulation and base plyInsulation and a base sheet are installed, then bonded or fastened according to the chosen method and deck type.
- Cap sheet and flashingsThe granulated cap sheet is installed with staggered laps, then walls, edges, drains and penetrations are flashed in matching materials.
- Cleanup and reviewWe clean the site, document the finished roof with photos and review care instructions and warranty terms with you.
What affects the price
Number of plies
Two-ply systems with a base and cap sheet cost more than a single layer, but offer added redundancy against leaks.
Application method
Torch, cold-applied and self-adhered systems differ in material cost, labor and the safety measures a given building requires.
Roof size and complexity
Many vents, curbs, skylights and parapet walls add flashing work that increases the total compared with a simple open roof.
Deck and insulation condition
Damaged sheathing and wet insulation must be replaced first, and new insulation changes material and labor needs.
Surfacing choice
Standard granule surfaces and reflective or specialty finishes have different material costs.
Building access
Height, street access, hoisting and protection of occupied areas influence time on site and overall cost.
Getting a price
Because these factors change from roof to roof, we don't publish one-size-fits-all prices. We inspect your roof for free and give you a written, itemized estimate before any work starts.
Every modified bitumen roofing job includes
- Free written estimate and roof inspection
- Permit handling where required for the work
- Fire-safety planning for any open-flame application
- Protection of the property, windows and entrances
- New base and cap sheets with sealed laps
- New flashing at walls, drains and penetrations
- Dumpster and debris removal
- Jobsite cleanup and magnetic sweep of the surrounding area
- Photo documentation before and after
- 10-year warranty on full roof replacements; written workmanship warranty on repairs, terms on our warranty page
Written workmanship warranty on every job; full roof replacements carry our 10-year warranty. Warranty terms.