Specs for a good EPDM roof?


Thanks to those who convinced me to go with EPDM on my 2/12 roof. Next question: what are the key specs to look for in a quality job? Here’s what I (think) I know so far:

  • 0.060 membrane
  • fully adhered with solvent-based adhesive
  • isocyanurate substrate (are there other options? Is this a generic name?)
  • use termination bar to anchor edges

Any special considerations for penetration points for venting?

Any rubber brand better than others? The guy I’m talking to uses RPI

This is the back side of a 24x36 cape. The back is a full dormer with 2/12 slope. On one side an addition roof with a 12/12 pitch butts up (about 1/2 way along 2/12 edge). Addition wall rises above 2/12 and is vinyl-sided.

Any advice appreciated



termination bar

without knowing / reading previous posts
it would be difficult for most to determine
what to tell you…size of roof, details to tie into
existing other roof, pictures would be helpful!!
If this is done already, just ignore me!!

1:02 PM ADDED NOTE…I would suggest a vented
iso panel, like Hunter panel cool vent…Of course, if your roofing on a flat wood structure with a conventional framed roof and adequate roofing and insulation, then a fastened recovery board would do the same thing.


Hire a contractor who will give you a epdm roof installed to the manufactures specs. The manufacture will inspect the roof after it is installed. Whatever doesn’t meet their specs will be listed on a punch list to be fixed by the contractor. Due to it being residential there may be no warranty from the manufacturer. but at least you will know that it is properly installed.


I hate the look of term bar. you should have him install a metal edge or even drip edge and strip it in. It looks a lot better and is a better job.


No need for term bar if fully adhered. That would be mech. fastened and as far as I am concerned in Vt in the winter we have no better option,



The manufactuer is not going to come out and inspect the roof.



If you use recovery board, you will need 1/2" x 6" plywood areound the perimeter. Then your recovery board. The recover board needs to be fastened with screws and plates not nails. The rubber needs to hang over 2" on all sides. The rubber needs to run up the shingle plan 2’.This will start you.


kind of off topic, and a just for general information.
Those of you that install various mfg, and thicknesses pf epdm, When using the extremely heavier epdm’s… …090MIL .100 MIL…Do you find any difficulty in winter installations as far as working the sheet as it gets colder…in other words…is .090 stiffer to stiff to put down as it get colder compard to .045…or is it almost an un-noticeable difference.


The most important spec for a EPDM roof is a qualified installer.

It is best to avoid applying EPDM when the temps are too cold.
Even if you keep your materials warm before installation you are still applying to a cold substrate.

That being said, experienced detail oriented roofers install EPDM at low temps all the time with good results.
Less experienced roofers try this and they end up with a problem roof.


If this is a residential application, the common mfr’s of EPDM (Firestone/Carlisle Syntec) wont offer a factory warranty.

GAF will offer a warranty on a residential application, but they only make TPO/PVC.

Genflex will offer a residential warranty, but it only covers the material.

Find a qualified installer. I would recommend TPO over EPDM, but thats just a personal preference.



The manufactuer is not going to come out and inspect the roof.[/quote]


Yea your probably right. I was just thinking if it were I, we could get the local rep to do us a “favor” and inspect the roof for the customers piece of mind. There would be no warranty but as a courtesy to the customer and a favor to us he would do it. That doesn’t mean it would happen in this persons situation.

This only something i would offer to the customer if it meant getting the job. The rep surely wouldn’t do it often.