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larry42 04-27-2007 10:12 AM

flat epdm roof problem
I have a flat EPDM roof, about 15 years old. It is a Carlisle system roof and has these round hold downs that are about 6 inches in diameter with a 2 inch part that screws on to the top of this thing with what looks like a vent under it. The outer 6 inch disk that contacts the roof mambrane has fins on it to grab for tighening down, I think. These things are attached on a grid pattern about 4 feet apart. The problem area is a low point on the roof, about an inch below the grade of the rest of the roof, with about 6 of these disks in the usually wet area. My question is--- can I unscrew these things and put a EPDM safe calke or sealer under them to stop the slow leak? They seem like a real dumb howd down method.
Thanks, Larry

RooferJim 04-27-2007 12:26 PM

Its probably more than 15 years old .It is what was called back in the day the Carlisle MARS system acronym for "mechanicly attached roofing system" cira early to mid 1980s. It was kinda one of those things invented by some nimrod in an office that had a really neat idea on paper but in practice didnt work very well. There were a lot of these neat idea roof systems that came and went.Im supprised it lasted that long


larry42 04-27-2007 01:04 PM

but how....
Thanks for the reply. I'd really like to tackle this my self. An electrician

was walking around up there and broke a couple of those hold downs whcih made it leak like crazy. Thats wht got me up there in the first place. I siliconed those up and the leak stopped, mostly. If there is a lot of water up there it seems to seep under those disks, so I want to unscrew them, butter them up with a epdm safe caullk to cement and tighten them down. Any reason not to do this? Thanks

RooferJim 04-27-2007 02:54 PM

Silicone is an OK temp but it needs to be patched with membrane. you should get a roofer.


Ed the Roofer 04-27-2007 08:32 PM

If you were going to try to patch these MARS plates and screws, I would probably completely back the screw out enough to fill the screw hole in with the manufacturers approved lap sealant, so that when you re-secure the screws in place, the threads are pasted with this product.

I would also liberally apply a continuous circular bead under the disc prior to it becoming screwed down, just enough so the disc pushes the additional sealant out of the circumferance of the plate.

After it oozes out of the outside diameter of the plate, I would take a "wet" finger, and smoothen the bead of sealant down so that the bead is equally high as the securing plate and tapers down to the epdm roof membrane.

Not an approved manufacturers patch, but it will keep the individual screws water-tight probably.


Talos4 04-28-2007 10:03 PM

One of the worst designed systems ever.

Who in their right mind thought it would be acceptable to punch a bunch holes through the membrane and then try to seal them with a plastic cover?

Probably the same ones that came up with uncured EPDM flashings.

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