Modified Bitumen Roofing Systems


Modified Bitumen roofing is asphalt-based and is a similar substance to Built-Up-Roof designed for structures featuring a low-slope or a flat roof. Modified Bitumen Roofing Systems can stand up to extreme weather conditions in any season using five protective layers. This is one of the most relied upon flat roofing systems available on the market today. The most common forms of Modified Bitumen Roofing Systems include SBS and APP which are additives to the process. The two most-utilized installation methods are conventional and inverted.

For a Bitumen roof, standard roofing asphalt requires modifiers to be added so that plasticizers that were eliminated during distillation are replaced. Fiberglass or polyester fiber matting reinforces Bitumen to increase strength and durability.
SBS and APP are two of the most common modifiers available. As SBS (styrene-butadiene-styrene) enhances membrane flexibility for greater expansion and contraction during temperature changes, APP (atactic polypropylene) increases the longevity of the entire Modified Bitumen Roofing system. Flexibility is often the most popular choice so the SBS synthetic rubber additive tends to have a higher prevalence.


The construction of a Modified Bitumen Roofing Systems includes five-layers of components in combination.

Insulation – Provides “R” value, or thermal resistance, to maintain internal temperature stability on the bituminous roof.
Modified Base Sheets or Plies – Utilizes SBS or APP modifiers as needed.
Modified Bitumen Membranes – Fabricated membrane sheets consisting of a co-polymer that is reinforced with polyester or fiberglass.
Adhesive – The bituminous roof is secured and seals in place through a waterproof material that contains a bonding agent which is applied cold or hot, with the use of roof welding equipment.
Surfacing – UV protection increases the life of the roof, saving energy while weather resistance keeps the roof from developing leaks or gaps.


  • Proven performance through years of use
  • Excellent waterproofing capabilities
  • Wide range of application solutions
  • A selection of top-surfacing options, such as “Cool Roofing”
  • Insulation can add further benefits with greater performance
  • Extremely durable with incredible tensile-strength
  • A bitumen roof can be rated for fire, wind, and hail
  • A long-lasting roof offers a competitive overall cost
  • Can be installed without flames or VOC
  • Modified Bitumen Roofing systems can have long-term warranties included

SBS Roofing

SBS is one of the easiest commercial roofing membrane systems to install, and it is very customizable. During the installation process, a number of reinforcements are utilized along with the asphalt, including fiberglass, polyester mats, scrims, and other materials.
Plus, SBS may be installed using a variety of applications including cold-applied, heat welding, self-adhered, mechanically fastened, and hot applications. The method of installation aside, correctly modified asphalt that includes SBS bitumen offers an extremely durable combination with outstanding recovery capabilities through a wide range of temperatures and under the most severe weather conditions. To be brief, a bitumen roof enhanced with an SBS roofing system is among the very best roofing solutions available in new construction design.

Benefits of SBS Roofing Systems
1. SBS bitumen is very compatible with all forms of flat roof systems.
2. Expect great resistance to the harshest weather conditions in every season, including extreme temperatures.
3. The lifespan of SBS Modified Bitumen is simply amazing, even in taking age and general wear into account. And SBS bitumen can significantly extend the life of a bituminous roof and serve the roof well even as it nears the end of its usefulness.
4. An SBS bitumen blend offers exceptional waterproofing protection for your roof and the rest of your property.
5. SBS modified roofing installation is easy and there are a number of available methods to choose from to achieve the right application for the structure.

APP Installation

APP Modified Bitumen Roofing Systems (Atactic Polypropylene) come in a selection of thicknesses and textures, including smooth and granule surfaces. They are also reinforced with a strong, non-woven polyester mat, or a trilaminate glass and poly mat, to give an APP roofing system strength in rooftop performance. The APP modified bitumen roof can be installed with a durable cold adhesive or with heat welding.
Most APP roofing system applications are done with the heat-welded method using a top surface in either a smooth or granular finish. The consistency of the texture and the uniformity in the thickness and design of the factory manufactured sheet produces excellent stability and greater flexibility in the membrane than a laminated built-up roof system can offer.

Highly specialized proprietary compounds together with certain grades of refined asphalt combine to enhance the durability, strength, and flexibility of the APP roofing system.
Thermal expansion and contraction, as well as structural movement, is managed by APP roofing through its elongation properties and flexibility, even under the most extreme temperature changes.
To reinforce the strength of APP modified bitumen, the membrane may include a tri-laminate mat consisting of high tensile fiberglass scrim, as well as a woven polyester.