Moisture barrier - nails

[Magnus tt]

We have a newly built house from 2023. In the attic, under the insulation, you can see that all the vertical studs in the interior walls have been nailed up against the horizontal stud and through the moisture barrier. This must be a fault in building technical terms, right?

 

[AG A]

No, that's not a moisture barrier. In the picture, you see a roof membrane. It replaces the sub-roof. It can also be used as a wind barrier in exterior walls. Nailing into it doesn't matter. Normally, construction plastic is also stapled up. However, a waterproofing layer in a bathroom should never be punctured.

 

[Magnus tt]

Is that really true? Is it not a membrane that is diffusion-tight? I.e., a membrane used instead of plastic?

There is no plastic elsewhere against the ceiling. Under the membrane in the picture (which is taken from the attic after the insulation has been removed), you see the nail battens and the framing to the interior wall. The interior wall is against the bathroom.

 

[useless]

As long as the nails remain in place, it's sealed. It's been done that way since moisture barriers began to be used over 50 years ago.

 

[Plupp 405730]

No, that is not a moisture barrier. The image shows a roofing membrane. It replaces the underroof. It can also be used as a wind barrier in exterior walls. It doesn't matter if nails are used on it. Building plastic is also usually stapled up.
However, a waterproof membrane in a bathroom should never be perforated.

It is a fall-through-proof vapor barrier, a so-called säkerhetsväv.

https://www.bygghemma.se/hus-och-by...sakerhetsvav-bison-2730-x-02-mm-25-m/p-851143

 

[Matti_75]

If you want, you can bend the nails and tape over them with tape intended for vapor barriers. As several have already pointed out, this is not a problem since the insulation will press down the plastic against the stud, preventing moisture from passing through as easily.

 

[Magnus tt]

If you want, you can bend the nails and tape over them with tape intended for vapor barriers.
As several have already pointed out, this is not a problem as the insulation will press the plastic against the beam and then moisture cannot pass through as easily.

Great - thanks!

 

[AG A]

It is a puncture-resistant vapor barrier, a so-called säkerhetsväv..

[link]

Yes, that's roughly what I meant when I said it was instead of underroofing. However, it's strange that it is said to be vapor tight and can be used as both a windbreak, building plastic, and as an underroof. You're not supposed to put a vapor barrier on the outside of the insulation.

 

[Matti_75]

Yes, that was roughly what I meant when I said it was instead of an inner ceiling. However, it is strange that it is said to be vapor-tight, and can be used as both a wind barrier, construction plastic, and as an inner ceiling. You must not place a vapor barrier on the outside of the insulation.

Roofing felt is also tight. It is the air gap in the roofing underlayment that makes it so you can't compare it to a wall.

 

[AG A]

Underlagspapp is also tight. It is the air gap in the underlay roof that makes it so you cannot compare it with a wall

Of course. Thanks, sometimes you ask without thinking first😄.