Insulate cold roof with clamp felt, price

Watch out, don’t get worked up. ---- Look at my photos again. There you see tongue and groove instead of OSB. And that only in the standing area, otherwise the insulation is open at the top. Set it up like that for yourself. And then ventilate now and then and that’s it. Also, no vapor barriers are glued, but vapor retarders, that’s a difference. It’s not absolutely tight. Karsten

Hm now you are making me unsure. Just like with Nordlys, the same was recommended to me by the professional. The material is already in the house and on Sunday we started laying the [Rauspund] in the attic. The plan is as follows:

Ceiling UG/attic: 23.5 cm [Rauspund], 22 cm [Klemmfilz], vapor retarder, battens, drywall panels. So far no problem.

Roof attic (triangular windows with tilt function in the attic present) 24 cm [Klemmfilz], vapor barrier, battens.

The material costs for the nearly 90 sqm roof were under 1,000. Of course, the attic is not heated, but ventilation is possible. Seems that’s not the best idea after all. So cancel everything? Basically, I trust the professional, but the arguments here do make sense to me^^

But it could of course also be that the controlled residential ventilation is pushing the humid air upwards somewhere.

The controlled residential ventilation should (normally) be a closed system and then would have nothing to do with the supply and exhaust ventilation of your attic.

Vapour barriers are not glued, but vapour retarders, that is a difference.

Nowadays, no one really installs proper vapour barriers anymore; that is why the terms are often used interchangeably. But you are of course right, we are talking about vapour retarders here.

What apparently has not yet really registered with people: Vapour retarders are not supposed to be "tight" (not even vapour barriers of earlier days were), but are intended to allow some diffusion so that any moisture that has penetrated (in summer) can dry out again.
The problem with this (especially with poor workmanship like with ) are leaks through which more moisture penetrates than is healthy for the construction, i.e. more than can dry out by itself again. This is all the worse if material with a comparatively high sd-value, such as OSB, is installed. The redrying through the OSB is usually many times worse than with a vapour retarder foil.



I would leave it. Either you want to use the attic in winter and then heat it as well, or it remains a pure storage or at best a hobby room for the warmer season. Then you can also leave the roof open.

We have lined an insulated attic with drywall; which is also not separately heated.

And no iso whatever hatch either. The ceiling to the attic is insulated and has a vapor barrier. On the insulation, tongue and groove boards; up to 2.5 cm short.

And that has been like that for almost 20 years.

So should an uninhabited attic always be uninsulated? I don't find that optimal either. Things are supposed to be stored there that don't like large temperature fluctuations. That would never be possible then?! Hm

Edit: how thick is the insulation of the slopes and with or without a vapor barrier?

Something like this can work well for decades, but can also lead to rotting ceiling beams within a very short time.

This falls into the category of "Smoking is not harmful, my grandpa smoked his 4 packs a day until he was 103 and died in a car accident."

These are of course always only theoretical considerations. Why it works well for you in reality and not for someone else who has invested a lot of energy into the "correct" execution would have to be examined on site.