Completely sealed ventilation hole in the ceiling? Possible?

[KnockOnWood]

I can't find the asphalt caulk anywhere in Stockholm.

Strange. It's available in every Byggmax store.
https://www.byggmax.se/tak/takpapp/takmassa-och-asfaltprodukter/asfaltkitt-p17370

It's that plastic piece I posted a picture of above that needs to be screwed. #13
I was thinking of whether to choose some kind of roofing nail, but it will probably be regular wood screws as it looks now.

Of course, you should use screws, isn't it solid wood under the roofing felt?
And in the pictures you posted, it says 16 screws.
Roofing nails don't fasten as well.

 

[swealp]

Strange. It's available in every Byggmax store.
[link]

Of course, you should use screws, there's probably råspont under the felt?
And in the pictures you uploaded, it shows 16 screws.
Felt nails hold much worse.

Other side of town has 1 in one store and 6 in the other store.
Feels a bit much to drive to the other side of town ;D

But K-36 should work, right? It says it's about the same.
http://www.katepal.fi/en/products/tiivistysliima-k-36/

Or Mataki:
https://www.hornbach.se/shop/MATAKI-Asfaltkitt-1-l/8041900/artikel-detaljer.html

Thanks!!!

 

[KnockOnWood]

But K-36 should work, right? It says it's about the same.
[link]

Or Mataki:
[link]

Thanks!!!

It's probably the same stuff.

And nothing to thank for, just returning the favor

 

[swealp]

Yeah, you have to say thanks!

 

[Lizzardo]

I have installed quite a few roof penetrations over the years with various sealing products and have concluded that ABRA Aqua Seal in a tube is my favorite