Flat Roof · Modified Bitumen
A flat roof with
layers to spare.
Modified bitumen is asphalt reinforced with polymer and built up in plies, the modern heir to the old tar-and-gravel roof. A tough, redundant, walkable surface for a flat or low-slope roof that takes abuse.
What it is
Asphalt and polymer, built up in plies.
Modified bitumen takes the asphalt of an old built-up roof and modifies it with polymers (SBS or APP) so it stays flexible in the cold and tough in the heat. It goes down in multiple plies with a granulated cap sheet on top, which gives the roof real redundancy: if the top layer takes a hit, there is still membrane underneath. It is the flat-roof system you choose when the roof gets walked on, takes foot traffic to service rooftop units, or just needs to be rugged. We install it in cold adhesive or self-adhered depending on the building and what is allowed over the deck below.
- System
- Modified bitumen, SBS or APP
- Build
- Multi-ply with granulated cap
- Application
- Cold adhesive or self-adhered
- Strength
- Redundant layers, walkable surface
- Best for
- Flat, low-slope, high-traffic roofs
- Use
- Residential and commercial
The plies
Redundancy built into the roof.
Modified bitumen goes down in layers, not a single sheet. A base ply and a granulated cap mean the roof has a backup built in: a scuff or a puncture in the top does not put water straight to the deck. That redundancy is why it holds up on roofs that get walked and worked.
The cap
A granulated surface that takes a beating.
The cap sheet carries mineral granules, like a shingle does, which armor the membrane against UV and foot traffic. It is a surface a tech can walk to service a rooftop unit without chewing up the roof, which matters on a building where people are up there regularly.
The application
Cold adhesive or self-adhered, by the deck.
How the membrane goes down depends on what is underneath and what is safe over it. We use cold adhesive where it fits, or self-adhere where that is the right call. We pick the method to the building, not to habit.
Old built-up or tar roof at the end of the line?
A project consultant walks the roof, checks the deck and the drainage, and tells you whether modified bitumen is the rugged fit or whether a single-ply membrane serves you better. The inspection is free, with a roof report.
What homeowners are saying
“Justin did a great job of communicating and was on the job site a lot.”
Gerald K. · Google
“Nick Mirth did an excellent job throughout the process our insurance claim!”
Tim C. · Google
“Great experience, very knowledgeable and customer friendly. I would highly Recommend.”
Kathy O. · Google