What is Mod Bit?
We have now passed the halfway point in our “What is a Substrate?” series. This blog has looked in recent weeks at EPDM, TPO, concrete and spray foam roofs, and today we will answer the question, “What is Mod Bit?”
Mod bit, which is a shortened name for modified bitumen, is asphalt-based and consists of multiple protection layers. It’s produced by blending raw asphalt with polymeric additives (synthetic rubber, or plastic), which increase the durability, strength, and flexibility.
This week’s blog will explore this roof system’s pros and cons and explain how a silicone roof coating restoration from Progressive Materials can help an aging mod-bit roof.
One major advantage for mod bit is its thickness. A mod-bit system with a granulated cap sheet is typically 240 MILs thick or more. On the other hand, a typical single-ply thermoplastic roof membrane is often 60 MILs.
That thickness helps boost mod bit’s durability. Its life expectancy is around 20 years.
Mod bit also has a strong resistance to low temperatures. It can withstand temperatures as low as -22 degrees Fahrenheit without cracking or breaking.
Like EPDM, mod-bit material is manufactured in large sheets or rolls. That makes it quick and easy to install. Additionally, the variety of installation methods can allow contractors to pick the best method for them and their clients.
Seams. On any single-ply system, the major disadvantage is almost always the seams. The seams on mod-roofs will eventually deteriorate and leak, putting your building and its contents at risk.
Ponding water is another disadvantage. When this occurs, mod bit will wear down faster than other flat-roof types like TPO.
Finally, many mod-bit roofs are black. That means the rooftop’s dark color attracts and absorbs heat from the sun — rather than reflecting it away from the building. That heat will eventually degrade a mod-bit roof. It will also mean hotter temperatures inside the building and higher – and more expensive — use of AC units.
How PM Can Help
One of the many benefits of PM silicone is that it will create a completely seamless membrane on the roof. The seams on a mod-bit roof won’t break down once it is coated with silicone because the seams will be nonexistent.
Another way PM can help is that ponding water is a non-issue for a silicone-coated roof. As an inorganic coating, PM Silicone can withstand ponding water for decades.
Our silicone coatings are moisture-cured. That means that once they’re cured they cannot absorb any more water, so ponding water won’t break down silicone as it can with other materials.
Additionally, white PM silicone reflects up to 88% of the sun’s UV rays and will not break down in extreme heat. It, like mod bit, also has elastic properties that allow is to expand and contractor with the seasons.
In conclusion, mod bit has proven its worth as a solid roof substrate. But seam leaks, ponding water, or high heat will eventually break it down. Like with most roof substrates, PM Silicone can help restore and make your mod-bit roof even stronger.
If you have questions about our company or silicone roof coatings, please contact us here: https://pmsilicone.com/contact.