Asphaltic Roofing Membranes

As parts of the asphaltic family of roofing solutions, SBS & APP Modified Bitumen and BUR are among the oldest and most common roofing technologies in use today, providing a reliable solution for both residential and commercial properties. Commercial asphalt roofing systems consist of two or more waterproofing layers, offering redundancy for durable waterproofing protection.

Field-tested more than a century, GAF asphaltic roofing materials provide durability and performance

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Time-tested

GAF expertise in asphalt roofing traces it roots to 1892 when the introduction of RU-BER-OID ready-to-lay asphalt roofing rolls revolutionized the industry. Today GAF manufactures a full portfolio of Mod-bit (SBS and APP) products under the RUBEROID® name, along with trusted brands GAFGLAS® and Tri-Ply asphaltic membranes.
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Solar-reflective options

GAF asphaltic membranes have come a long way. Cool Roof Rating Council–rated Solar Reflective Cap Membranes are now available, including EnergyCap™ and UltraClad™ Membranes.
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Hybrid solutions

By combining characteristics of multiple roofing technologies, such as SBS Mod Bit and TPO, hybrid systems can increase the overall robustness of the assembly.
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Commitment to quality

GAF asphalt roofing solutions are specifically formulated with durability in mind. Using only the high-quality raw materials, GAF's products are thoroughly tested to ensure performance.

Asphaltic roofing systems

built up roofing system

BUR (Built-Up Roofing)

BUR roofing technology has been around for over a century. It consists of melting bricks of asphalt in a large metal kettle and mopping that asphalt in-between a base sheet, ply sheets and lastly a cap sheet. Ply sheets and additional layers of asphalt can be added until the desired thickness is reached. While cap sheets are very popular, some jobs are finished with a layer of gravel over the asphalt.
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SBS (Styrene Butadiene Styrene)

SBS (Styrene Butadiene Styrene)

This synthetic rubber allows the SBS sheets to achieve greater elongation ratings than other asphaltic systems. SBS systems have a wide range of application methods as they can be hot-mopped, cold-applied, heat-welded or self-adhered. A typical SBS system consists of two plies of roofing membrane. First, a ply of smooth-surfaced SBS base sheet is installed, usually over insulation or cover board. The system is finished with a granulated cap sheet applied over the smooth base/ply sheet.
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APP (Atactic Polypropylene)

APP (Atactic Polypropylene)

APP features asphalt that has been modified (modified bitumen) to include atactic polypropylene – a plastic that allows the roofing membrane to protect against UV rays and weather events. APP is typically applied via a torch – a key difference from SBS. Like SBS, most APP systems consist of 2 membranes, a smooth sheet and a granule cap sheet. However, APP sheets are typically installed over either a BUR base sheet or thermal barriers as many substrates can’t be directly torched.
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EnergyCap™

EnergyCap™

Although not a separate type of roof technology like BUR, SBS or APP, EnergyCap™ roofing membranes are Bright White granulated cap sheets that reflect sunlight away from the roof and are Rated with the Cool Roof Rating Council for their reflective properties. There is an EnergyCap™ cap sheet available for each of the roofing technologies mentioned above.
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Asphaltic roofing installation methods

hot mopped

Hot-Mopped

One of the oldest application methods still used today, involves melting blocks of asphalt in a large kettle and spreading the melted asphalt on the roof with mops.
torched

Heat-Welded/Torch-Applied

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cold mopped

Cold-Applied

The installer will attach the roofing membrane by applying a liquid adhesive (i.e.,Matrix 101) with a tool such as a notched squeegee or an applicator gun to the substrate or previously applied layer of roofing material.
self-adhered

Self-Adhered

This fast growing asphaltic installation method involves rolling out a membrane and peeling the film backing to adhere the membrane. This method can increase the speed of installation over the other three methods and does not produce unpleasant odors.

Frequently asked questions

Roofs of essential buildings that need to stay open and operational at all times.

BUR is a solution that has been used for over 100 years. The redundant applications allow for increased protection against damage and leaks.

Roofs that need the reliability of a redundant asphaltic system without the odor and labor required for hot mopping. APP sheets are also used to recover existing roof systems.

APP is often used in smaller commercial roofing jobs, especially in urban areas. APP sheets are torched on to the surface below, therefore there is no need for a kettle, buckets or the inconvenience of getting asphalt onto the roof. In addition, APP systems typically consist of fewer plies than BUR jobs, allowing them to be installed faster and with a smaller labor force. Switching from a hot mopped application to a torch application will also reduce the odor around the work location allowing for more comfortable conditions for the workers and building occupants. A CERTA (Certified Roofing Torch Applicator) certification is required for a roofer to use a torch.

APP membranes are classified by ASTM numbers, types and grades.
ASTM D6222 – APP sheet using polyester reinforcement
ASTM D6223 – APP sheet using both polyester and glass fiber reinforcement

ASTM D6222 and D6223 have two type classifications, Type I and Type II. Typically Type II will have a larger mass and higher physical properties than Type I. There are two grades of APP sheet:
Grade S: the sheet has a smooth surface
Grade G: the sheet has a granule surface
ASTM number, type and grade are specified by the architect in most cases.

For roofs requiring the reliability of asphalt with more flexible application methods and labor availability. Introduced in the 1970’s, SBS features asphalt that has been modified (thus called modified bitumen) with the polymeric material SBS. Like APP, SBS can also be applied utilizing a torch (heat-welding). A CERTA (Certified Roofing Torch Applicator) certification is required for a roofer to use a torch. Many local ordinances also restrict the use of torches on roofs due to their risk as a potential fire hazard. Unlike APP, SBS can be applied in a variety of other ways including hot-mopped, cold-applied or self-adhered. Cold-applied applications are popular because they don’t produce as much odor as hot-mopped and do not require professional certifications like torching. Self-adhered is also a popular method because there is virtually no odor and it is typically faster to install.

SBS membranes are classified by ASTM numbers, types and grades:
ASTM D6162: SBS sheet using a combination of both polyester and glass fiber
ASTM D6163: SBS sheet using glass fiber reinforcement
ASTM D6164: SBS sheet using polyester reinforcement
ASTM D6162 and D6163 have three type classifications, Type I, Type II and Type III.
ASTM D6164 has two type classifications, Type 1 and Type 2. Typically, the higher the type, the larger the mass and physical properties.

There are two grades of SBS sheet:
Grade S: The sheet has a smooth surface
Grade G: The sheet has a granule surface
ASTM number, type and grade are specified by the architect in most cases.

For buildings that require ENERGY Star® certification or to be LEED® certified.

Utilize an EnergyCap™ sheet with any BUR, APP, and SBS system for projects that require the reliability of asphalt roofing and Energy Star® and LEED® certified solutions.

A great benefit of roofing with asphalt is the variety of technology and installation methods that are available.

PVC membrane swatch colors: white, tan, gray, and light gray.

1See the applicable manual for installation temperature instructions and ranges at https://www.gaf.com/document-library.
2GAF warranties and guarantees do not cover leaks or other damage due to wind speeds in excess of 55 miles per hour (unless additional wind coverage is purchased on eligible jobs). Refer to gaf.com for more information on warranty and guarantee coverage and restrictions.
3GAF warranties and guarantees do not provide coverage against punctures (unless additional puncture resistance coverage is purchased on eligible jobs). Refer to gaf.com for more information on warranty and guarantee coverage and restrictions.
4Require the use of RUBEROID® "EnergyCap™" Products.
5See the applicable manual for installation at https://www.gaf.com/document-library. See applicable warranty or guarantee for complete coverage restrictions.