Modified Bitumen Roofing
SBS & APP Commercial Roofing Systems
Modified bitumen combines the proven performance of built-up roofing with the convenience of single-ply application. Available in SBS (rubber-modified) and APP (plastic-modified) formulations for any climate.
Why Choose Modified Bitumen?
Multi-Ply Protection
Redundant waterproofing layers
Proven Performance
40+ years of commercial use
Climate Options
SBS for cold, APP for hot
Easy Repairs
Simple patch and overlay
SBS vs APP: Which to Choose?
Styrene-Butadiene-Styrene
- Excellent cold weather flexibility (down to -40°F)
- Self-healing in warm temperatures
- Superior elongation and fatigue resistance
- Best for northern climates
Atactic Polypropylene
- Superior UV and heat resistance
- Excellent dimensional stability
- Heat-weldable seams
- Best for southern/desert climates
Torch Application Safety
Torch-applied modified bitumen requires certified roofing professionals trained in open flame procedures. Fire watches, proper equipment, and adherence to NRCA safety guidelines are mandatory. Consider self-adhered alternatives for occupied buildings or fire-sensitive locations.
Johns Manville
Johns Manville DynaFlex SBS
$200-$350
per square
DynaFlex is a premium SBS modified bitumen membrane featuring exceptional flexibility and elongation. Its styrene-butadiene-styrene modifier provides rubber-like characteristics that allow the membrane to stretch and recover.
Thickness
160-180 mils
Surfacing
Granule or smooth
Lifespan
20-30 years
Warranty
20-30
Key Features
Pros
- •Excellent cold weather performance
- •Superior elongation and flexibility
- •Self-healing in warm temps
Cons
- •Torch application requires expertise
- •Higher cost than basic BUR
- •Granule loss over time possible
Firestone Building Products
Firestone SBS Plus Self-Adhered
$250-$400
per square
Firestone SBS Plus is a premium self-adhered modified bitumen membrane that eliminates the need for torches or hot asphalt. It features a split-release film for easy alignment and positioning.
Thickness
135 mils
Surfacing
Granule
Lifespan
20-25 years
Warranty
20
Key Features
Pros
- •Safe, no-flame installation
- •Faster installation time
- •Immediately waterproof when applied
Cons
- •Higher material cost
- •Temperature-sensitive application
- •Primer required on most substrates
GAF Commercial
GAF Liberty SBS Self-Adhering
$225-$375
per square
GAF Liberty SBS is a premium self-adhering modified bitumen roofing system designed for superior performance and ease of application. Features FAST adhesive technology for instant bond.
Thickness
135 mils
Surfacing
Ceramic granules
Lifespan
15-25 years
Warranty
15-25
Key Features
Pros
- •FAST adhesive system
- •Color options available
- •Instant waterproofing
Cons
- •Premium pricing
- •Requires specific primers
- •Temperature limitations
CertainTeed Commercial
CertainTeed Flintlastic APP
$180-$300
per square
Flintlastic APP is a premium atactic polypropylene modified bitumen membrane designed for superior UV resistance and high-temperature performance. Ideal for hot climates and exposed applications.
Thickness
150-180 mils
Surfacing
Granule or polyethylene film
Lifespan
20-30 years
Warranty
20-25
Key Features
Pros
- •Superior UV and heat resistance
- •Excellent dimensional stability
- •Strong heat-welded seams
Cons
- •Less flexible in cold weather
- •Requires torch installation
- •Not self-healing like SBS
IKO Commercial
IKO Torchflex Hot-Mopped
$175-$280
per square
IKO Torchflex Hot-Mopped is a versatile SBS modified bitumen membrane designed for hot asphalt application. This traditional method provides excellent adhesion and is ideal for complex roof details.
Thickness
160 mils
Surfacing
Granule
Lifespan
20-30 years
Warranty
20
Key Features
Pros
- •Proven traditional method
- •Excellent substrate adhesion
- •Good in cold weather install
Cons
- •Requires hot asphalt kettle
- •More labor intensive
- •Fumes and odor during install
Leading Modified Bitumen Manufacturers
Firestone Building Products
Est. 1980 • Indianapolis, Indiana
Firestone Building Products is a leading manufacturer of commercial roofing systems including high-p...
Johns Manville
Est. 1858 • Denver, Colorado
Johns Manville offers a comprehensive line of modified bitumen roofing products with industry-leadin...
GAF Commercial
Est. 1886 • Parsippany, New Jersey
GAF offers a full line of modified bitumen products including both SBS and APP membranes for commerc...
CertainTeed Commercial
Est. 1904 • Malvern, Pennsylvania
CertainTeed provides reliable modified bitumen roofing solutions backed by comprehensive warranties ...
IKO Commercial
Est. 1951 • Calgary, Alberta
IKO manufactures a wide range of modified bitumen membranes designed for durability and ease of appl...
Application Method Comparison
| Method | Speed | Fire Risk | Cost | Best For |
|---|---|---|---|---|
| Torch Applied | Fast | High | $$ | Unoccupied buildings, new construction |
| Self-Adhered | Fast | None | $$$ | Occupied buildings, healthcare, schools |
| Hot Mopped | Medium | Medium | $$ | Large commercial, hybrid BUR systems |
| Cold Applied | Slow | None | $$ | Detail work, repairs, sensitive areas |
Need a Modified Bitumen Roof?
Connect with certified commercial roofing contractors who specialize in modified bitumen installation and can recommend the right system for your building.
Get Free QuotesInstallation Considerations
Substrate Requirements
Modified bitumen can be installed over various substrates including plywood, OSB, concrete, gypsum, and existing BUR or mod bit roofs. Proper preparation and priming are essential.
Multi-Ply Systems
Most specifications call for a base sheet plus cap sheet (2-ply minimum). Premium systems use 3-ply with an interply for maximum protection and longer warranties.
Weather Requirements
Self-adhered products need temperatures above 40-45°F. Torch and hot-mopped systems can be applied in colder weather. Avoid application in rain or on wet substrates.