Learning About Modified Bitumen Roofing!

In recent years, the application of modified bitumen to commercial buildings has increased. It is believed that thisBranham Roofing Company material covers approximately twenty percent of the commercial building top market. The features and benefits of this material can be vouched for by professionals who have been in the roofing business for a long time.

Modified bitumen is an asphalt-based sheet membrane that has been altered to provide lasting elasticity and durability. Although there is an increasing growth of modified bitumen on the market, not much is known about this type of rubberized material. This article will describe in detail the types, advantages, installation process, components, and necessary inspections of this element.


There are two types of modified bitumen well-known to architects, contractors, engineers, and developers based on the kind of chemical compound used in its manufacturing.

  • Styrene-Butadiene-Styrene (SBS) – This type is self-adhering for safety reasons while others are installed using hot asphalt. When this modifier is mixed with glass fiber reinforcement, it produces an elastic, durable, and weather-proof material with an extensive service life with an increased overall performance and excellent elasticity limit.
  • Atactic Polypropylene (APP) – This material is welded using a propane-fueled torch. The back of the material has rubberized asphalt and when heated will adhere firmly on the substrate. It should not be directly applied to wood decking due to possible fire hazards.


This product is commonly applied to low-slope commercial roofs or even to some residences. In general, modified bitumen offers the advantages of: ultra-violet rays resistance; water-proof; weather resistance; high durability; thermal shock and crack resistance; fire resistance; ease of installation; and low maintenance requirements.


This material can be easily applied using several installation methods including: heat welding; hot-mopping; cold-process; and the latest innovation of self-adhesion. The torch application uses a propane tank placed at the center for easy access and eliminates the need to transfer the tank while the sheet is being laid. A flaming torch can be moved along the rolled sheets intersections and sheathing while the material is gradually unrolled forward until adhered at all points. Self-adhering material allows for the sheet to be rolled out and the release paper peeled to adjoin it to the substrate, although this method is messier and time-consuming.

Basic Components

The modified bitumen roof has five or six basic components that can be tacked together when building the structure.

  • Insulation – The layer that delivers a stable substrate and has excellent ‘R’ value.
  • Base Ply Sheets – The rigid board applied on top of the main ingredient.
  • Bitumen Membranes – The main ingredient, factory fabricated sheet (APP or SBS modified) reinforced with fiberglass.
  • Adhesive – A waterproofing agent that glues the plies together.
  • Surfacing – A smooth or granular surface coating that is highly reflective to ultraviolet rays. This comes in different options such as mineral, gravel or cold coatings, depending on personal preferences or as recommended.
  • Flashing – Water proofing material that is installed on the perimeter and any projections.

Life Expectancy

The secret to prolonged service life lies in a well-established maintenance program. Begin by inspecting the present condition of the system. The frequency of inspections does not depend on the type of membranes used but rather on the pitch of the roof. Flat roofs require that an inspection twice a year, while steep slopes need an annual check-up. While an inspection can be a “do-it-yourself” project, it is better to let professionals assess the condition and provide a detailed report. Keeping the material in the best possible condition can help it extend beyond its expected service life.

Modified bitumen roofing is widely used around the world today. Many contractors recommend this type of material because of the benefits that it has to offer; however, its single drawback is that not much is known about this highly marketed, rubberized asphalt material. Reading this article will have hopefully provided a better understanding about this material and allow it to be considered as a great roofing option!

Let Schulte Roofing Be Your Brenham Roof Company Contractor!

Do you need the services of a y familiar with modified bitumen roofing? Call the professionals at Schulte Roofing at 800-367-7663 who help all Brenham area customers with any questions about these structures!