As we discussed earlier commercial roofing has come a long way since the first tar and gravel built up roofs. In this post, we will begin discussing some options available that both address environmental concerns and liability concerns with typical flat or low slope roofing.

The first advances in typical asphalt roofs produced modified bitumen membranes which essentially are an improvement on the durable asphalt and felt ply roofs. These membranes usually consist of fiberglass, polyester or a combination of fiberglass and polyester mats impregnated with modified bitumen. Modified bitumen is produced by modifying typical asphalt improving its elasticity and giving it rubberized properties.

Modified bitumen roofs usually consist of 2 to 3 plies either hot mopped down with hot asphalt or torching it down with an open flame torch. For purposes of this post we want to stick with the most advanced roofing techniques and cutting edge technology. Therefore, we will address the newest modified bitumen roof addition- the self adhered modified bitumen roof membrane. Traditionally, modified bitumen membranes added longevity and versatility compared to the built up tar and gravel roof but did not cut down on installation liabilities for roofing companies or building owners.

However, with the advent of the self-adhered membranes, modified bitumen roofs have paralleled or even surpassed their single ply roof membrane counter-parts in the liability game. Self adhered membranes accomplish this by first eliminating hot 450 degree asphalt and open flames to torch or heat weld the membranes down. These self adhered membranes come from the manufacturer with adhesive on their backside. Which simply means that these membranes need to be rolled out and they will adhere to the roof substrate and to each other. No flames, no heat, no hot asphalt means lowered liability for both roofing company and building owner. But what allows self adhered membranes to surpass their single ply membrane counter-parts is that many times they are installed with low VOC components and can be recycled lessening their impact on the environment- a concern everyone should be placing their attention towards.

Also, recent advances have produced a modified bitumen membrane that exhibits the solar reflective and cool roof capacities equaling the single ply solar reflective membranes such as TPO. CertainTeed’s Coolstar and Firestone’s UltraWhite modified bitumen membranes are examples of these asphalt cool roof options. These options further lessen the roofing company and building owner’s environmental footprint. Deflecting solar rays also increases the roofs lifespan meaning less turnover and less environmental waste.

Basically, as technology advances, modified bitumen membranes provide the traditional, proven and unsurpassed durability of an asphalt based roof yet now provide low liability and solar reflective capacities comparable to their single ply roof membrane counter-parts.

In our next post we will discuss the fastest growing of roofing options- the single ply market, namely TPO (thermoplastic polyolefin).

If you have any questions regarding commercial roofing options feel free to contact Cobalt at (800) 820-4182 or see us at