diffusion plastic against chimney?

[Marive]

Hi, I'm wondering how to solve the connection of the plastic to the chimney? You want it to be tight, but how do you solve it? Is the plastic affected by the warm chimney? Does anyone know or have any smart ideas?

 

[juggler]

A year too late, here is a solution:
I screwed 100mm wide U-profile steel studs around the chimney at the height of the spaced panel.
(It was one short side that was screwed against the chimney.)
Then gaps were sealed with fire sealant foam, which is pink-colored.
The vapor retarder was taped to the short side that is furthest from the chimney.
You can also clamp the plastic between the spaced panel and steel profile.

Tip: The fire sealant foam can also be used to seal between the vapor retarder and stone wool-insulated kitchen duct.