Introduced over 40 years ago, modified bitumen is a durable roofing system that has stood the test of time and continues to be one of the most popular widely used roofing systems today.
One of the biggest drawbacks to modified bitumen is that extreme heat is needed to properly weld sheet seams, unless using cold-process adhesives. Heat is typically applied with open-flame torches, but if not used properly, these flames can start fires on the roof and in the underlying structure.
The Mechanically Fastened/Attached System uses fastening plates to secure the membrane. This system provides faster installation times without the use of adhesives and seam tapes. Membrane seams are then heat-welded with specialty hot-air equipment. Mechanically attached is the most prevalent method of installing TPO membranes.
Mechanically attached systems carry warranties of up to 25 years.
The Fully Adhered System uses TPO bonding adhesive to adhere and secure the TPO membrane to the insulation board or recovery board. This method does not require the use of fastening plates to secure the membrane. Membrane seams are then heat-welded with specialty hot-air equipment.
Fully adhered systems carry warranties of up to 30 years.
A ballast roof system is a loose-laid roofing system that is not anchored or adhered to the decking, except for the perimeter and around penetrations/curbs, and is ballasted throughout, generally with gravel. Ballasted is the least prevalent method of installing TPO membranes and is used less and less today.
One reason why modified bitumen is one of the most popular roofing systems is how easy and quick the installation process can be for an experienced production crew. A quicker roof installation often times results in reduced labor costs, potentially saving you thousands on your new roofing system.
Modified bitumen is an excellent commercial roofing system because it is resistant to heavy foot traffic, punctures, and tears. Featuring plastic- or rubber-based polymeric binders in its formulation, modified bitumen is flexible and expands or contracts with the building, making it suitable for many different climates.
Modified bitumen sheets are manufactured under tight quality control, resulting in consistent thickness. Manufacturers assemble the torch-preparation linings, waterproofing binder, weather-resistant surfacing, and fabric reinforcement into sheets with uniform physical properties and thickness. This consistency guarantees a reliable and proven performance from the product.