I know this is debated occasionally, but I've now had a kitchen and bathroom drywalled by carpenters as part of a renovation.
Parts of the house are an old timber house with an extension from the late '70s with a stud frame and fiberglass insulation, asfaboard, and wood paneling without an air gap.
Previously there was plastic sheeting, and there were no indications of problems.
Today, it was discovered by chance that no new vapor barrier was installed, just the boards, and I'm questioning whether that's okay?
In the bathroom, there is no vapor retarder installed either, and I'm not sure if it's an absolute requirement or not there?
Parts of the house are an old timber house with an extension from the late '70s with a stud frame and fiberglass insulation, asfaboard, and wood paneling without an air gap.
Previously there was plastic sheeting, and there were no indications of problems.
Today, it was discovered by chance that no new vapor barrier was installed, just the boards, and I'm questioning whether that's okay?
In the bathroom, there is no vapor retarder installed either, and I'm not sure if it's an absolute requirement or not there?
Interesting... I would think that in fiberglass wool, you don't want condensation/moisture, so on a wall with fiberglass wool there should be some sort of vapor barrier. On the log wall, plastic is probably unsuitable and a vapor brake in the form of paper or similar is better... So that moisture can dry out.
Then some say that a gypsum board without holes, like those with fiberglass wallpaper or plastic wallpaper, is as tight as a plastic film... so I don't know in practice...
Then some say that a gypsum board without holes, like those with fiberglass wallpaper or plastic wallpaper, is as tight as a plastic film... so I don't know in practice...
don't you have a moisture barrier in the bathroom? That sounds really odd.
I am very doubtful about the advantages of a vapor retarder over a vapor barrier.
I am very doubtful about the advantages of a vapor retarder over a vapor barrier.
there should be special cuffs at all outlets and penetrations if I understand correctly. I have an old house without plastic (unless the previous owner put it on a wall he insulated from the inside, I almost think so)
I think plastic film and glass wool are purely theoretical products; in practice, they'll leak like a sieve... But they are supposed to perform tightness checks, so maybe they'll get it right? But after a couple of renovations, hanging a TV, pictures, etc., it will probably be unsealed again. It's probably best to avoid stone and glass wool...
I insulated two rooms from the inside with linisolering and a vapor barrier made of paper, I tried to be extremely careful with all the penetrations, as it is still a forgiving material. Plastic, I believe, could become a real disaster if moisture gets in but not out.
I think plastic film and glass wool are purely theoretical products; in practice, they'll leak like a sieve... But they are supposed to perform tightness checks, so maybe they'll get it right? But after a couple of renovations, hanging a TV, pictures, etc., it will probably be unsealed again. It's probably best to avoid stone and glass wool...
I insulated two rooms from the inside with linisolering and a vapor barrier made of paper, I tried to be extremely careful with all the penetrations, as it is still a forgiving material. Plastic, I believe, could become a real disaster if moisture gets in but not out.
How could the moisture dry inward if it is so humid there that it has gone into the wall?
I'm not talking about bathrooms now. In regular rooms, you might imagine that humid air seeps through holes in the plastic and condenses inside the wall's fiberglass insulation. It can't dry inward because of the plastic, and outward it's below freezing, so even if it theoretically could continue out, it would likely go very slowly in winter.D Daniel 109 said:
It doesn't take much moisture under plastic for it to start molding, rotting, or generally becoming unpleasant.
If you have a solid wooden house, I think it can withstand quite a bit of moisture if they are allowed to dry out now and then. Just throw a piece of wood on a rock in the rain and weather; as long as it can dry occasionally, it lasts surprisingly long...
We had put up plastic sheeting (vapor barrier) but had to take it down on the builders' orders.D Daniel 109 said:
There will of course be a moisture barrier/sealing layer. From what I read, a vapor retarder is preferred over a vapor barrier in wet rooms to avoid the risk of trapping any moisture between two tight layers, but it also depends on the choice of sealing layer.
As mentioned, you already have a tight layer, so an additional one is not needed.
It dries out because it's cold outside. But I don't understand how you can think it will dry toward the place where the moisture comes from.J JohanLun said:
I would be worried about moisture trapped between gullfiber and plastic not drying in any direction... but everyone becomes content with their own thing. You are welcome to have plastic-covered walls if you like. I try to avoid it... But I also live in a 110-year-old house. Plastic in an old solid wood construction is something that quite a few people agree involves risks; it's also not necessary. If you mix old solid frames with gullfiber and plastic, you should probably know what you're doing.D Daniel 109 said:
Gullfiber is completely moisture open. It does not trap any moisture. Problems arise when you don't know what you're doing.
Fine. I will avoid it anyway.D Daniel 109 said:
Quite a few people don't really know what they're doing, and regarding combining an old wall with plastic and gullfiber, I honestly don't know myself how the theory behind that would work or how you would theoretically get the plastic film to be completely sealed. Therefore, I choose a simpler solution that is less demanding and more forgiving.
For TS's question, it would probably be good if you explained, if you know what you're doing, the theory behind your statement so TS can be aware when he builds in that way.
I am more curious about the theory behind your statement.
I believe many plastic films are not airtight due to penetrations and seams, thus they will not function as intended in theory.D Daniel 109 said:
I also believe it is better to have a material that does not trap any moisture that mistakenly gets behind the vapor barrier.
But if there is vapor pressure from the inside, an expensive permeable film would actually lead to even more moisture in the wall, not less.