Topcoat roofing product

February 11, 2008 7:10 PM

Any roofers out there? Local contractor is recommending a gaf Topcoat product that I'm having difficulty evaluating.

We're in a small 48 unit condo complex with a standing seam metal roof. We're having leaks on the edges of the roof where it meets painted cinderblock or painted wood siding firewall at a 90 degree. We've had a contractor suggest GAF TopCoat or something similar over the seam and a foot over on the roof and a foot up the firewall. I'm having difficulty determining if this is a good option. Google returns very little other than some of the product details.

posted by striker to home & garden (2 comments total)

Call another roofer or two in your area. They give free estimates, and if they come up with the same remedy it's probably a good option.
posted by kuujjuarapik at 7:35 PM on February 11, 2008

From this description, it sounds as if the leak is where the roofing meets the sidewall. If you're looking for something other than a temporary fix, consider the source of the problem and fix that. The topcoat product (disclaimer, I'm not familiar with that one) will temprarily remedy the symptom, but probably not be a long-term solution. Just guessing, based on your description.

First, evaluate if there is sidewall stepped flashing installed. If so, repair the stepped flashing if that's what's leaking. The idea behind this type flashing is to provide an "L-shaped" flashing that goes up the sidewall, is layered "behind" the exterior wall sheathing and comes out over top of the metal roof to provide a continuous plane for any penetrating moisture to follow.

If no sidewall flashing is installed - best practice is to install it. See details on page (9) of this pdf http://www.semetals.com/MetalRoofing/VERTILOK_Detail_Manual.pdf (sorry, I don't have time to find a better detail). Use a butyl sealant where the flashing is installed into the masonry joints.

As suggested by kuujjuarapik, get some other roofers to evaluate and explain their methods of fixing the problem you're experiencing. If they cannot explain it to you, keep getting estimates until you have a good understanding.
posted by mightshould at 7:46 AM on February 12, 2008