Modified bitumen, often called mod-bit or torch-down, is asphalt reinforced with polymers and built up in layers. A typical system has a base sheet, one or more ply sheets and a granulated cap sheet on top. Multiple layers mean multiple lines of defense against water.
Why owners choose modified bitumen
- Redundancy. Two or three plies instead of one.
- Durable surface. Holds up well to foot traffic from AC techs and other trades.
- Familiar and repairable. Most roofers can maintain it, and repairs blend in.
- Reflective options. White granulated cap sheets or a reflective coating reduce heat.
Torch-down or self-adhered?
Torch-applied sheets are heated with a torch to bond them. Self-adhered sheets stick without an open flame, which is often the better choice on occupied buildings, near wood framing or where fire watch is a concern. We'll recommend the right method for your building.
How we install it
- Tear off to the deck and replace any damaged decking.
- Add tapered insulation or crickets where water ponds.
- Install each ply to an approved system, with lapped and sealed seams.
- Flash walls, curbs, drains and penetrations, and finish with edge metal and coping.
Modified Bitumen Roofing FAQ
How long does a modified bitumen roof last?
Commonly around 15 to 20 years, and sometimes longer with good drainage, a reflective surface and regular maintenance.
Is modified bitumen better than TPO?
Neither is best for every building. Mod-bit offers multiple layers and handles foot traffic well; TPO is lighter, has fewer seams and is very reflective. We'll explain the trade-offs for your roof.
Do you install mod-bit on homes too?
Yes. Flat sections on homes, like Florida rooms and garages, often use modified bitumen. See our <a href="flat-roofing.html">flat roofing page</a>.
Where we work
Doral · Medley · Hialeah · Miami Gardens · Miami · Miami Beach · Sunny Isles Beach · Aventura · Fort Lauderdale · Pompano Beach · Hollywood · Pembroke Pines · Miramar · Davie · Sunrise · Coral Springs · and every city in Miami-Dade and Broward