Roofing Directory

Materials / APP Modified Bitumen

APP Modified Bitumen

asphaltic

A modified-bitumen membrane in which the asphalt is modified with atactic polypropylene (APP), giving a plastic-like, heat- and UV-resistant sheet typically torch-applied. Distinct from SBS modified bitumen, which uses a rubber-like elastomeric modifier better suited to cold-flex applications.

Category family
asphaltic
Typical lifespan
15–25 years
Typical wind resistance
FM-rated assemblies vary by attachment
Typical fire rating
Class A
Weight per square
100–150 lbs
Cost band
$$
Slope suitability
low
Typical warranty
10–20 years
Pros
  • strong UV and heat resistance from the APP modifier
  • durable plastic-like surface
  • multi-ply redundancy
  • established asphaltic chemistry
Cons
  • torch application carries fire risk
  • less cold-temperature flexibility than SBS
  • labor-intensive versus single-ply

Related guides

Asphalt vs. Metal vs. Tile Wind & Fire Ratings New Roof Cost

Sources