Existing PVC Roof with Asphaltic Adhesive Membrane

Hey there everyone, first and foremost, thank you for taking the time to review and respond.

I see thru the many comments below that PVC (flexible… or just in general) does not play well with asphaltic materials of all sorts and there have been a few work arounds.

We approved an asphaltic adhesive membrane for added protection for the coping with the understanding it would be used with the TPO we approved. The replacement of the existing PVC roof with the TPO did not occur, so the sub consultant used the asphaltic adhesive membrane with the existing PVC roof membrane that wrapped up and over the parapet.

The membrane began to turn to goo in some several spots on the building and now dripping on the façade.

Yet the owner wants an adhesive / membrane that will help tie down the coping and protect against any penetrations used to nail down the coping.

Are there any reasonable solutions (liquid or membrane applied) that can facilitate this owner directed request or solution?

You DO NOT want asphaltic products mixed with PVC membrane. The contractor can buy a PVC pressure-sensitive cover strip to overlay the coping but it isn’t big enough to do the wall, over the coping, and down the other side… Just make sure that the cover strip isn’t being used with asphalt mastic. Have the contractor submit a detail for sealing off the fasteners for the coping from the manufacturer of the PVC membrane.
Frankly, I’d recommend that all the wall membrane be removed and replaced, ensuring that the asphalt is also removed. If the contractor cannot remove all the asphalt, have the wall covered with Dens Deck, or a similar product, and re-roofed.

2 Likes

Thank you for your response.

Unfortunately, I don’t think reroofing is in the cards at the moment. We did reroof part of the buildings to a new TPO system. The owner liked the asphaltic product used and asked that it be used throughout the campus.

Now we are where we are.

Been calling Sarnafil for the past 4 days to talk about solutions. They really do not like to pick up the phone is all I have learned.