Roof Membrane Leaking

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Slider27

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I'm in Colorado, where relative humidity is low and sunlight is plentiful, but it is late January.

I have a PVC membrane on a flat roof that is leaking, dripping through the seam in the OSB sheathing and from a capped roof vent penetration. I'm assuming the scrim, the foam buildup for pitch, and the OSB are all saturated.

Am I correct in assuming that mold and rot will be a problem and that the roof needs to be opened up and dried out before moving on to repair/replacemement?

If this is the case, how long do I need to air out the OSB before starting the repair?
 
It all depends how wet the subsurface is and if there's any rotted decking. What are your plans repair or replace the existing membrane?
 
We will repair the existing material for now. It's a blown seam in the membrane. The rest of the membrane looks good. Winter isn't the optimal time for a replacement.

Water is dripping directly through the OSB, so I assume it is saturated. The underside looks ok, but it feels spongy when on the roof.

It is a 15 year old PVC membrane, so replacing it is certainly in the discussion.
 
Most single plus lifespans are in the 15 year span. When weather permits, tear off the existing system. Replace any damaged decking and install a new roof surface. PVC or TPO roof systems require special tools and knows to properly install, most homeowners don't have the skills to install these systems.

GAF makes a fairly easy to install system that a novice can install and have a good result.
 

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Thank you oldognewtrick -

Professional roofers will be doing the install.

This Old Dog is way past wrestling with rolls of roofing, plus days of A&E welding.
 
I have seen a few pvc membranes installed, after tearing off rubber or typical modified bitumen flat roofing, so far not very impressed.

Extremely slippery, as in impossible to safely walk on to clean gutters.
Very stiff and seems brittle.

Hard to flex and bend to surfaces without heating it, and appears iffy at seam seals, the concept might be great but I have seen only discouraging installations so far.

Hopefully, other folks have had better results.
 
hi, my 2 cents: when you get the roof deck uncovered and (if) you end up replacing sheathing: use a trad plywood (or preferably one of the plywoods that's treated to take a bit of moisture without repercussions). OSB may save a few material bucks and be fine if it never gets wet, but the worst when moisture hits and esp. moisture thats undiscovered for a length of time. Its also "softer" than trad. plywood -- and may explain a little of the spongy walk you mentioned
 
hi, my 2 cents: when you get the roof deck uncovered and (if) you end up replacing sheathing: use a trad plywood (or preferably one of the plywoods that's treated to take a bit of moisture without repercussions). OSB may save a few material bucks and be fine if it never gets wet, but the worst when moisture hits and esp. moisture thats undiscovered for a length of time. Its also "softer" than trad. plywood -- and may explain a little of the spongy walk you mentioned
Agree, you get what you pay for.
 

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