Modified Bitumen
Modified bitumen is perhaps the most common of residential low slope roofing systems. Modified bitumen is installed in 3' rolls, either torch applied using flame heat to weld the cap sheet to the base sheet(s) or self adhering using factory applied adhesives on the various components. The duration of your warranty term on modified bitumen is determined by the number of layers.
Quick specs for a typical modified bitumen roof assembly is as follows:
1 layer of base and 1 layer of smooth black modified bitumen - 10 year system rating.
1 or 2 layers of base with 1 layer of smooth modified bitumen and an application of an approved reflective coating - 12 year system rating. (Please note that this reflective coating may require periodic maintenance or re-application to achieve a 12 year life cycle)
2 layers of base with 1 layer of granulated modified bitumen - 15 year system rating.
1 or 2 layers of base with a smooth modified bitumen mid-ply and a granulated modified bitumen cap sheet - 20 year system rating.
People often wonder why their modified bitumen roofs last only 10 or 12 years and do not understand that is usually what most other roofers may be offering.
Choosing a roofing system for your property may be overwhelming if you don't know the pro's and cons of each membrane. There are no one size fits all solutions. Each low slope roofing membrane may be superior for some conditions, while inferior for others. The determination of this longevity is how the new roof is installed. For example a mechanically attached 45 mil single ply roofing system may be rated to last 15 years, while a fully adhered 60 mil roofing system with insulation may be rated to last 20 or 30 years