Inspection hatch, vapor barrier?

[kalubah]

I am going to insulate my sloped ceiling with linen wool + diffusion-tight paper. I would like to have an inspection hatch so I can keep an eye on the outer roof and especially one of the rafters that has previously been moisture-damaged.
The hatch must break through the diffusion barrier. Does anyone have tips on how to solve it in a good way?

 

[dusthall]

If it's a metal hatch, then it's possible to install a sealing strip to seal the hatch, right?!...

 

[storkarp]

I made the hatches from plywood painted with wet room paint on the cold side + foam insulation. Along with this, regular window sealing in rubber. Should be sufficiently tight.

 

[kalubah]

Thanks for the response. I talked to a colleague who suggested that I skip the hatch and install a hygrometer instead. Cheaper and easier, so I'll probably do that. d^_^b