Low slope EPDM

[Bryan]

I am looking for information on EPDM installed directly over plywood. You can see the H clips and nail heads showing through the membrane. I am pretty sure this is wrong and would like something to back it up. Also on the same inspection they ran the asphalt shingles down over the membrane. I remember reading somewhere, can't remember where, that this should not be done cause of an incompatably issue between the rubber and asphalt. Any information or direction would be helpful.

Bryan

[Jim Katen]

Originally posted by Bryan

I am looking for information on EPDM installed directly over plywood. You can see the H clips and nail heads showing through the membrane. I am pretty sure this is wrong and would like something to back it up. Also on the same inspection they ran the asphalt shingles down over the membrane. I remember reading somewhere, can't remember where, that this should not be done cause of an incompatably issue between the rubber and asphalt. Any information or direction would be helpful.

Bryan

Just going by memory here, but I believe that EPDM shouldn't be installed directly over plywood. The plywood surface is too rough. There should be insulation board or, at minimum, fleese between the plywood and the rubber.

EPDM certainly reacts badly to some asphalt formulations, but you'd probably have to consult with the EPDM manufacturer to find out whether or not asphalt shingles, in their dry state, pose a risk.

- Jim Katen, Oregon

[Scottpat]

This is an EPDM installation guide by Firestone. I have used it for years. It should help. I'm with Jim, you can not put EPDM directly on the decking, it needs an insulation board to cushion and protect it.

Download Attachment: EPDM_Guide.pdf

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[RickSab]

Thanks Scott, for sharing a great reference.

[BornaRoofer]

You can go directly over plywood or osb but it must be screwed down with no clips and be very clean and no splinters.

In fact firestones 30 year epdm system is over osb directly but its screwed with counter sunk screws.

I would always recommend a cover board of some type since most wont put the wood down right and there will be problems.

Yes you can install shingles over the epdm at tie ins on a slope. It should be run up under the shingles a good couple of feet and stop the shingles a few feet above the flat.

Epdm is not compatible with asphalt but theres not alot of oils coming out of a shingle and it will be fine. Mastic would be another story.

If the nails are already popping up the life of the roof will be very short.

[mthomas1]

Firestone has a very nice on-line documentation system, for example here's the page with attachment layout information for various materials/applications:

http://manual.fsbp.com/technicalresourc ... mentguide/

[Bryan]

Scott,

Thank you for the download, it had info that was helpfull. The hole roof system on the building was a mess. It was all low slope with architectural shingles and EPDM. The details were very poor and will most likely cut the life expectancy of the roof system in half.

Bryan

[hausdok]

Hi,

Were those architectural grade shingles the standard asphalt-fiberglass type or were they Malarkey brand modbit shingles specifically designed for a low slope application over a layer of ice and water shield?

ONE TEAM - ONE FIGHT!!!

Mike

[Bryan]

NO, it's asphalt shingles over felt. 2 1/2-3/12 pitch, lots of issues and some ponding in the "valley"

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[BornaRoofer]

Looks like three roof systems.

Shingles

Epdm

ModBit

[Bryan]

Originally posted by BornaRoofer

Looks like three roof systems.

Shingles

Epdm

ModBit

No, it was good old roll roofing not Mod Bit.. The buckets of tar and sealent were still on the roof top. The building was renovated 8 years ago and reroofed this last spring. The original EPDM did not last long.

Bryan

Bryan