[roobinsteen]

I'm helping out a friend, who is planning to replace the roof on an addition to his mother's house. The roof that we'll be working with is extremely low slope, nearly flat in fact. I went up there today with a 4' level, and measured a 3/4" drop over the 4' length of the level, which translates to 3/16" per foot. A few years back I replaced the roof on a low sloped addition to my home, using the certainteed's flintlastic roofing, a "peel and stick" SBS product. However, my roof was about 2:12, and I'm certain I can't use the same sort of product on something that's as low-pitched as his mom's roof. I was looking into EPDM roofing. Am I correct that EPDM will be acceptable for a roof of this slope? Also, how is EPDM usually purchased (as a custom sized full sheet, or does it come in standard rolls/sizes, etc)? And finally, I've read a few things online that suggest it's a fairly diy friendly product to work with (for someone who is detail oriented and handy, of course). Have others on here found that to be true? The roof is just under 4 squares in size. Thanks.

 

[craig11152]

You can use the SBS on that pitch. In the case of Flintlastic they reference a 1/4"-12 as the good practice and modern code but also recognize it isn't always practical so they punt to drainage. The roof cannot hold water or pond after rain. The industry standard for ponding is 48 hours after a rain.
Did you measure in several spots? That 3/4" in 4 feet is pretty close to a 1/4-12 anyway.

My point would be, if you are comfortable with the "peel and stick" SBS its OK to use verses a new learning curve for EPDM.

 

[roobinsteen]

You can use the SBS on that pitch. In the case of Flintlastic they reference a 1/4"-12 as the good practice and modern code but also recognize it isn't always practical so they punt to drainage. The roof cannot hold water or pond after rain. The industry standard for ponding is 48 hours after a rain.
Did you measure in several spots? That 3/4" in 4 feet is pretty close to a 1/4-12 anyway.

My point would be, if you are comfortable with the "peel and stick" SBS its OK to use verses a new learning curve for EPDM.

Thanks for the advice. We're still in the planning stage, and I'm still curious about EPDM. Like I said, I only used the peel and stick SBS one time (on my own roof), so it's not like I'm hugely more experienced in that. Would anyone like to comment on whether or not EPDM is doable for a non-professional roofer, especially when compared to a system like Flintlastic? I'm not yet sure what the material cost difference will be. When I used that on my roof, I did the full 3-ply system. I still feel a bit nervous about using an SBS system like Flintlastic on a roof as low-slope as my friend's moms. In most places, it barely has the required minimum slope of 1/4:12. It's more like 3/16:12. Hard to tell exactly, because there are already 2 layers of old roll roofing on there, so the surface is a bit uneven.