EPDM Rubber Roof VS SBS Modified Bitumen Self Adhering

8 Replies

Hi BP Community, 

I just purchased a foreclosure in Walton, Upstate NY as a getaway from NYC and while I knew the roof needed to be fixed, I just found out that some areas of the roof need to be entirely replaced as they have a very low pitch and currently have shingles (Not sure why they did that in the first place).  This is all new to me, so I am learning as I go.  

My question is - Do I go for the EPDM rubber roof or the GAF self-adhesive Modified Bitumen roof option? So far I got two contractors and one prefers rubber and the other mod bit. Both seem to make compelling arguments, so it's hard to make a decision and the more I research online the more confused I am since I have found articles and videos suggesting one over the other.   

I would REALLY appreciate some feedback as I have NO CLUE.  



Hi Leandro

Both the options have their own pros and cons and also both are used extensively these day. EPDM is long lasting, easy to install but comes in Black and white option only whereas GAF self-adhesive Modified Bitumen option has more elegant and attractive way as it comes in different colours. in terms of durability i would prefer EPDM method. Whereas, if you looking to save money and more aesthetic roofing option you can opt for modified bitumen roofing.

EPDM roof is a better system although it has more pieces to it so if not installed properly it will leak
- make sure they tear off old roofing down to the sheathing or plank and start fresh
-ask your contractor what size of rubber roll he plans on using ( they come in a variety of lengths and width, the less seams the better)
-the rubber rolls come in different thicknesses or mils 45 mil is a minimum
- make sure it an fully adhered system where they are gluing the runner to the fiberboard
- As long as they are using primer/glue/ seam tape on all your seams as well as some sort of decent termination bar at the roofing edges you should be fine
-how’s you slope on the roof currently? ( if there are any sags or dips a good contractor will shim those with sleepers under the fiberboard or sloped foam ( the foam is extremely expensive tho) to ensure you have a flat functional roof when completed
-I hope this helps let me know if you have any other questions ?

Thank you so much for your feedback! It has been very difficult to find a reliable roofer in the area. So far I just found one contractor that would only do the mod bit roof. He explained that due to the extreme weather in this area of upstate NY he has seen rubber roofs leak all the time and has switched to mod bit and has had no issues with leaks. Last month in the same week weather went from 30 degrees and snow on Monday to 80 degrees on Wednesday. He explained that the adhesive of the mod bit sticks much better leaving less space than rubber once it’s layered it down, so the expansion and contraction that causes the rubber to fail doesn’t occur with this product. Does this make sense to you? Thanks again for your advice!


I would agree it’s easier to screw up an EPDM roof than a mod bit roof but The company I worked for put down hundreds of EPDM roofs over the years in northern Minnesota and never had an issue as long as the process was followed.  What type of mod bit is he recommending a hot or cold application?

This is the product he is recommending:

GAF SBS Self adhering mod bit.


That’s a decent product if your going to use the mod bit. Although I do feel the EPDM is a Superior product if you can’t get it installed by a competent roofer than the mod bit is nice as there is less pieces/ and a much simpler installation process.

-if you can get references of roofs that he’s done that are a couple years old (talk to those customers and you can get an idea as to how they have held up for a couple seasons)
- See if he can throw in a manufacturers warranty GAF has an excellent warranty program that might be valuable if you have any issues down the road

I personally wouldn't trust a roofer that switched from EPDM because he had too many leaks. It is a very easy system to install properly and if the roofer isn't capable of doing it, then they are capable of screwing up every other system out there. The self adhered is idiot proof for the most part, but it isn't even in the same class as a properly installed .060 EPDM system that will last 30-40 years with minimal maintenance (seams need to be inspected/sealed every 5 years or so)

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