Interfacing 6" Flange to Metal Roof

[GasSavers_Erik]

The fig 1 and 2 method (post 8) you posted a pic of would be easiest to do, but may look a little odd unless you could paint the whole flange to match your roofing (since so much of the flange is showing).

They make a rubber molding that matches the seam profile (it is used for sealing both sides of the ridge cap). You could use one of those on the downhill side with the post #8 idea.

[GasSavers_maximilian]

The way my setup is I can put the flange underneath the uphill metal sheet quite easily, so I'm actually going with my setup from post 5. Trimmed approximate holes for the ribs with tin snips, then used my angle grinder to slowly enlarge them to fit the actual piece. Came out pretty well. I'm waiting for the silver paint to dry and then I'll caulk and rivet the sucker. Should look decent once it's done. Thanks for all the input.

I can definitely see how if you didn't have a seam right at the correct spot you'd want to use the Selkirk approach, since it can just plop down on top.

[GasSavers_maximilian]

Here it is. I normally don't subscribe to the philosophy of "more is better", but this time was an exception. I put a ton of caulk on the underside of the flange before riveting them together. It's not like you're going to be able to tell from the ground. Maybe it's OK that my spot welder's not working, since I have to wonder how it would've interacted with the caulk. Mess up the tips at the very least.

[GasSavers_maximilian]

Got it installed. It even looks a little like my drawing. Need to buy another 2' section of insulated pipe. The photo's at an odd angle, but since thunderstorms were rolling in I couldn't spend a lot of time on it. I had to cut a big hole in the roof to get the attic shield in there. It was either that or crawl through 75' of 16" deep cellulose. Thanks again for the comments, they helped me sort things out.

[GasSavers_Erik]

Looks nice and like it will shed water well.