Modified Bitumen Roofing Manufacturers List & Website Directory

By Roof Online Staff • Last updated April 5, 2024

For more about modified bitumen, see our article on Modified Bitumen Roofing and our Modified Bitumen Roofing Cost Guide.

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Modified Roofing Manufacturers
A roll of SBS-modified bitumen cap sheet (image courtesy Siplast)

Modified bitumen (commonly referred to as “mod bit”) roof membranes are manufactured in sheets, with layers of modified asphalt applied to each side of a reinforcement fabric, much the same way as asphalt shingles are made, but produced and sold as rolls that are 25 to 30 feet long and typically 39 inches wide. The word “bitumen” refers to the asphalt which forms the waterproofing component of the roof membrane. The asphalt is modified to improve its performance and durability. The modifiers are most often either a synthetic rubber called SBS (styrene-butadiene-styrene) or a plastic called APP (atactic polypropylene). The modifiers are added to the asphalt during the manufacturing process to create a more flexible, resilient, and temperature-resistant roofing material. Also like asphalt shingles, a granule coating is typically embedded in the weathering surface of the modified bitumen sheet.

Modified bitumen roofing systems are commonly used on buildings with low-slope (flat) roofs, and are normally installed with two or three layers forming the final roof membrane.

Key Properties of Modified Bitumen Roof Membranes:

  1. Enhanced Durability: The addition of the modifiers increases the tensile strength and elasticity of the asphalt, making the roofing system more resistant to tearing, punctures, and weather-induced degradation than traditional asphalt built-up roofs. Modified bitumen is particularly well-suited for smaller flat roofs than receive a lot of foot traffic, as their puncture resistance is far greater than than the cheaper and more common single-ply roof systems typically seen on commercial buildings.
  2. Improved Flexibility: Mod-bit roofs can better accommodate building movements and temperature-induced expansion and contraction than traditional built-up roofing, reducing the risk of cracks, tears, and splits.
  3. Waterproofing: These membranes have excellent waterproofing properties, and the fact that they are installed with multiple layers means they have a built-in redundancy which better protects the building.
  4. Compatibility with Asphalt: Repairs on mod bit roofing systems are generally simple and can often be made by the building owner or facilities manager using commonly available asphalt roofing products like roof cement.
  5. Versatility: Modified bitumen can be installed in various ways, including torch-applied, in cold-applied adhesives, or using self-adhering sheets, and also surfaced in various ways, including with granules, reflective coatings, or both.

Importance of Choosing a Reputable Modified Bitumen Manufacturer:

  1. Quality Assurance: A reputable manufacturer will have high standards during the manufacturing process, which helps ensure that the modified bitumen membrane will be of high quality. This contributes to an optimal service life and performance level for the roof.
  2. Innovative Solutions: Leading manufacturers invest in research and development to improve their products. They may offer advanced mod-bit membranes and accessories with superior performance characteristics.
  3. Comprehensive Warranty: Established modified bitumen roofing manufacturers usually provide substantial warranties that cover materials and, in some cases, workmanship. Some may even offer a certain amount of guaranteed repair work each year for a set period after installation. This can be a valuable part of your investment in your roof.
  4. Technical Support: A good manufacturer will have a technical department that offers technical support and guidance, from selecting the right product for your specific needs to providing installation guidelines and post-installation support if any problems develop.
  5. Qualified Contractors: Reputable modified bitumen roofing manufacturers will typically only sell their products to roofing contractors that they have trained, tested, and approved and will provide you with a list of certified contractors in your area.
  6. Compliance with Standards: Reputable manufacturers adhere to industry standards and building codes, ensuring that their modified products are safe, effective, and eligible for use in various jurisdictions.

Choosing a high-quality modified bitumen manufacturer is an important first step toward ensuring your roofing system’s performance and service life.


If you are a reputable and qualified modified bitumen roofing manufacturer and feel that we’ve overlooked your company, feel free to contact us to ask to be added to this list.

Modified Bitumen Roofing Manufacturers List