Vapor barrier under ridge beam or not?

[swealp]

Hello best byggahus.se!

How do you think the vapor barrier should be taped?

Should it cover the entire ridge beam from underneath or end just next to the sides?

Attached is a picture of both options.

Thanks for the help!

 

[huggan]

If you can't go over, you must go under, and tape all the joints and corners.

 

[shomakie]

I went forward then nervous towards the beam and tape.

 

[Autodidak1]

Hello best byggahus.se!

How do you think one should tape the vapor barrier?

Should it cover the entire ridge beam from underneath or just end close to the sides?

Attaching a picture of both options.

Thanks for the help!

A bit of an afterthought, but what you should do is lay the plastic over the ridge beam before the trusses are installed, and then fold the plastic up to the underside of the trusses. If you want the ridge beam visible, a halfway decent solution is to tape and fasten the plastic to the ridge beam, not an optimal solution.

Construction-wise, it's better to let the plastic go around the ridge beam, then you can clad the ridge beam afterward to hide the plastic.

 

[arkTecko]

Why would it be a problem to clamp and tape the latch against the beam? I can't see any problem with that?

 

[shomakie]

I taped and then I also clamped the last rule against the plastic.

 

[Autodidak1]

Why would it be a problem to pinch and tape the barrier against the beam? I can't see any problem with that?

Problem or no problem, it won't be as tight as doing it properly

But in this situation, you do the best you can.

 

[shomakie]

I've seen some houses being built where they don't put any plastic over the beam before it's supposed to hang and dangle before it's time for the interior.

 

[Autodidak1]

I have seen some houses being built where they don't put any plastic over the beam before it's supposed to hang and dangle before it's time for the inside.

I've seen that too, but why not do it the best way?

No one just squeezes a vapor barrier on the side of wall studs and thinks it's perfect; there's a reason you want to overlap and tape the vapor barrier. It's just laziness or forgetfulness not to do it as well as possible.

It's in the roof where there is the greatest risk of increased moisture load, so that's where the vapor barrier is most important.

But the houses don't collapse immediately because of that mistake...

 

[swealp]

Hello! Thank you for all the valuable answers!

Then we proceed with the vapor barrier.

However, it also needs to be covered with ceiling gypsum, which will probably result in 500 holes in the ridge beam. :/ I'd rather not put up studs as it's already cramped by the sleeping loft.

How do you think we should do it?

Thanks!!