ᐅ Vapor barrier foil between exposed rafters – how should it be installed?

Hello everyone,

The roof has now been completely redone.
I have been thinking a lot about how to install the vapor retarder effectively.
I definitely want to keep the rafters visible, I know it requires a lot of work.
I have attached 3 photos; in the last photo there is a sketch showing two of my proposals marked in red and yellow. The green marks indicate the adhesive points.

What do you think?

Thanks and best regards, Phil

That should have been done beforehand; I can't imagine you can get that fiddly part properly watertight.

With a generous amount of adhesive tape and careful workmanship, it will work out. Or is there anything fundamentally against it?

Your cut sketch looks fine, but the question is how you plan to access it. I see potential issues more at the top and bottom.

You will probably also have a condensation problem at the joint. I would simply seal it off or, for aesthetic reasons, screw on another rafter.