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Hello. We are in the process of having a standing seam metal roof installed. Our 4/12 pitched roof transitions to a flat roof on three sides with two valleys feeding into the flat roof on the corners (pls see pic) We had the flat roof covered with TPO which runs at least a foot up the sloped roof on the three sides. My question is: How do you properly transition the panels to the flat roof? My contractor wants to just end the panels six inches up the slope and apply polyurethane sealant to the ends. So the panels will be only vertically fastened down their nails-trip, snaplocked and the cut ends will sit on sealant 6 inches upslope on the TPO flat roof. There will be No cleat to cut and hem the panels to. He claims the fasteners for the cleat would create possible leaks and that this was “how they always do it.” I proposed a cleat on top of butyl tape and then sealant. Please advise and thank you.
I would suggest a heavy gauge flashing that extends several inches up the pitch roof and several inches out onto the flat roof. I would like to see uphill underlayment lapped over the uphill edge of the flashing if possible. You would then cleat for the steep roof, several inches above the transition. One purpose of the flashing is so that, when the TPO has to be replaced (before the metal roof has to be replaced), the flashing can be lifted up and new roofing can be worked in under it. Otherwise, you're in a bit of a tough spot when the TPO needs replaced.
Thank you Todd for your quick reply. I'm a detail guy... so a few more questions.
So my method mentioned of starter panel (cleat) over butyl tape is the correct way with added flashing and several inches of setback up the slope.
Our home is in southwest Florida (as you might of guessed by the pic) where we get a lot of rain... especially now going into summer. The manufacturer has a transition flashing but it is for metal panel to metal panel. It's standard dimension is 6 1/2 inches with a transitional break to another 6 1/2 inches.
My questions now are:
If we have to customize the flashing to fit...How many inches upslope for the cleat and how many inches onto the flat TPO roof for the flashing?
The flashing will not be hemmed to a Z bar but will be sitting on a flat TPO roof. Do we use butyl tape or the polyurethane sealant to prevent water from getting underneath it?
The goal would be to have the flashing as tight to the TPO as possible. If water should wash up, it should drain back out and not get high enough to cause any problems. I'd prefer to not seal the flashing if at all possible. If it is sealed, if anything happens at all that water or condensation is draining down from the back side of the metal, it will be trapped. I'd make the flashing as big as possible ... maybe 15" up the steep slope and 9" out over the TPO ... but the cleat maybe 8" above the transition.
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