Asphalt Flat Roof Systems
A popular choice for residential and commercial properties, Modified Bitumen offers a common and reliable solution for low-slope roofs. Understanding your options is key to a lasting investment.
Get Your Flat Roof EstimateSBS vs. APP Modified Bitumen
When choosing an asphalt for your flat roof, your two main options are SBS (rubberized) and APP (plasticized) bitumen. Each offers unique advantages.
SBS (Styrene-Butadiene-Styrene)
"Rubberized Asphalt"
- Superior Flexibility: Expands and contracts with temperature changes, ideal for climates with significant fluctuations like the Northeast.
- Impact Resistance: Rubberized properties resist hail and heavy foot traffic.
- Cold Weather Performance: Maintains flexibility in cold temperatures, reducing the risk of cracking.
- Versatile Application: Can be cold-applied with adhesive or self-adhered (peel and stick).
APP (Atactic Polypropylene)
"Plasticized Asphalt"
- High Temperature Tolerance: High melting point makes it exceptionally stable in hot climates and resistant to intense sun.
- UV Resistance: Excellent resistance to ultraviolet radiation helps prevent premature aging.
- Torch Application: Installed via torching, which melts the asphalt into a liquid for a strong, monolithic bond.
- Puncture Resistance: Its plasticized nature offers good puncture resistance once cooled.
How to Choose?
SBS is preferred for colder climates due to its flexibility, while APP often excels in hotter climates for its UV resistance and high-temp stability.
Asphalt Flat Roof Replacement Steps
Replacing a flat roof is a multi-step process requiring skilled labor to ensure a watertight, long-lasting system.
Roof Tear-Off
All existing roof layers will be removed to expose the underlying roof decking.
Inspect & Replace Decking
The exposed decking is inspected for signs of rot and sagging; any damaged sections will be replaced.
Vapor Barrier (Optional)
A vapor barrier may be installed over the deck to prevent moisture from entering the roofing system.
Install Polyiso Insulation
Polyiso board, the most common insulation for flat roofs, is installed to provide thermal resistance.
Install Modified Bitumen
The core of the roof. The base and cap sheets (SBS or APP) are carefully laid out and adhered to the substrate.
Flashing and Edge Detail
Critical areas like pipes, vents, and skylights receive meticulous flashing to prevent leaks.
Final Inspection & Cleanup
A thorough inspection ensures all components are properly installed and the site is left clean and tidy.
Trust the Flat Roof Experts
Flat roofs are more complex than sloped roofs. Hire a reputable and experienced contractor specializing in low-slope applications to ensure a quality, lasting investment.
Speak With a Flat Roof Specialist