Questions on a low pitch roof

[fqp25]

I haven't had the chance to do many low pitch roofs. First of all I think this roof is EPDM. Secondly, what are these square marks showing through. Some are rigid in the middle like a bolt head. Could not see underside of roof.

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This picture is the roofing material stretched over something. It is very spongy in the corner.

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This patch, by the stack is a different material, maybe PVC? It has bumps on it. How is this sealed on the ends, torched down?

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Frank

[kurt]

Probably EPDM, and those squares are the fasteners that the membrane is adhered to.

EPDM goes down with solvents, not heat. The grey goobs of caulk around those repairs look wrong. Different material as a patch is definitely wrong.

[BornaRoofer]

It is Epdm and its seamed with tapes or adhesives. Those are the plates and screws that secure the insulation to the deck and possibly the epdm is also adheared to them. It appears that there is a epdm square at each plate. The material used for the flashings is form flashing or uncured epdm. Sometimes it does have a textured surface and it looks like the right stuff. The caulk looks like the wrong stuff but it wont make or break a good roof.

[kurt]

I was told by a Carlisle guy that certain caulks, i.e., Vulkem or equal, would damage the EPDM. I thought you shouldn't use caulk, had to be solvent/adhesive.

I've never seen uncured EPDM; it's always been the same smooth material for flashing.

[BornaRoofer]

No, polyurethanes, silicone ect wont hurt epdm. Any type of roof cement or oil based product would though.

The caulk is used after the adhesive for a temporary seal until the glue cures and for T bar, Boot tops ect.

Regular (cured) epdm will not form through angle changes or around pipes and such things. Thats what the uncured form flashing is for. Its also used for T joints, vertical patches, curb corners ect. The material on the stack and gas line in the pics is form flashing as is the strip in on the boot.

They used to use neoprene but it ages and splits.

[kurt]

Good info. As Johnny, used to say, "I did not know that....".

[msteger]

Just curious.. what is that vent for at the bottom of the 3rd picture?

[BornaRoofer]

It appears to have been capped for years.

[fqp25]

Originally posted by msteger

Just curious.. what is that vent for at the bottom of the 3rd picture?

There has been a few different restaurants in this building. That vent didn't come through the present finished ceiling.

Frank