[RE-wrenches] Flashing vs Sealant... again (is sealant code defensible?)

[Troy Harvey]

Glenn, I understand where you are coming from, However....

My concern is that flashings could be worse. Unless the flashing design supports sealant + flashing, it will most likely be worse. I've never seen a L-foot leak, but I've seem many flashings that rely on gravity leak. An L-foot sealed with silicone, holds that sealant in compression. It is a pretty ideal gasket. A flashing relies on gravity, but that only works until ice dams up. It also means you are modifying the roof to get the flashings under the shingles, which adds its own risk.

After all, when roofs get low pitched enough, nobody uses gravity as a means of shedding water, they all use sealants or welded membranes.

Nobody so far has commented on the code defensibility of sealant systems... it there anything in the code specific that is addressing this in the IRC/IBC? Or is it just a ICC rating issue that address assemblies?



> Yes it is more expensive – but it is like insurance, you don’t need it until you need it, but then there is no substitute for it. Of course if you are big enough with deep enough pockets you can take more chances with roof penetrations, and maybe you will not run into a call-back for a leaking roof. But if you do, wouldn’t you have a stronger position with the customer by saying all penetrations were flashed in accordance with standard roofing contractors and manufacturer’s specifications instead of ‘well I shot everything full of sealant and it is what I have been doing for years/hundreds of holes in roofs’…
> 

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