I'm going to close up an exterior door but I'm a bit unsure about which layers to use. The house is from 1963 and I believe it's constructed with:
- Wood siding
- Battens
- Dark brown board, asphalt board?
- Glass wool insulation with silver side closest to gypsum
- Gypsum
I assume the silver side of the insulation is some kind of vapor barrier?
What I guess to get it correct is that I would do:
- Wood siding
- Battens
- Asphalt board
- Insulation
- Plastic foil
- Gypsum
Is this correctly done?
- Wood siding
- Battens
- Dark brown board, asphalt board?
- Glass wool insulation with silver side closest to gypsum
- Gypsum
I assume the silver side of the insulation is some kind of vapor barrier?
What I guess to get it correct is that I would do:
- Wood siding
- Battens
- Asphalt board
- Insulation
- Plastic foil
- Gypsum
Is this correctly done?
Best answer
No plastic wrap, use other materials.
The house is very likely not diffusion-tight, then you should not build with plastic, the risk of condensation is very high on both sides of the plastic.
If you build diffusion-tight, you should have from the outside in:
Facade panel, battens, wind barrier, insulation lying horizontally in one layer, insulation standing vertically one layer, plastic, insulation again on the warm side then OSB or plywood, finally gypsum.
Regards, P-A
The house is very likely not diffusion-tight, then you should not build with plastic, the risk of condensation is very high on both sides of the plastic.
If you build diffusion-tight, you should have from the outside in:
Facade panel, battens, wind barrier, insulation lying horizontally in one layer, insulation standing vertically one layer, plastic, insulation again on the warm side then OSB or plywood, finally gypsum.
Regards, P-A
There is no risk of condensation against the plastic. Feel free to use plastic.
Having double layers of insulation in different directions is not applicable if you're closing off a door. This is done to minimize thermal bridges from the studs. There is no advantage to having insulation inside the vapor barrier. If the wall's insulation is thinner than 150mm, you definitely should not have it that way. The reason for building like this is that it works if you have more insulation, and the electrician does not damage the vapor barrier when installing electricity. There is no building physics advantage to it, rather the opposite.
OSB or plywood is not needed.
Having double layers of insulation in different directions is not applicable if you're closing off a door. This is done to minimize thermal bridges from the studs. There is no advantage to having insulation inside the vapor barrier. If the wall's insulation is thinner than 150mm, you definitely should not have it that way. The reason for building like this is that it works if you have more insulation, and the electrician does not damage the vapor barrier when installing electricity. There is no building physics advantage to it, rather the opposite.
OSB or plywood is not needed.
Now we have different experiences in construction solutions, writing as you do gives mixed messages to the questioner.D Daniel 109 said:
There are rules to apply, there is pure logic, and there are downright stupid things to write. What you're writing is not completely wrong, not nonsensical, just more like unthought-out. Unthought-out in the sense that you don't add plastic in a house that didn't have plastic before, it's a different construction technique.
If you read, I wrote about how to build diffusion-tight, I gave a description of how to do it.
The point of OSB or plywood behind the drywall is known to those of us who build as having the function that you can attach things to the wall, drywall holds poorly.
A doorway being insulated should, according to me, according to me, have the frame removed to prevent thermal bridges.
Insulating on both the cold and warm side of construction plastic is not because our electricians are bad (you didn't say they are bad, but it can be perceived as such), they manage to avoid puncturing diffusion-tight systems if they are involved from the start. Carpenters are a bit stubborn, often blaming construction mistakes on other professions, I know! And I'm fully aware that my text can come across as a bit grumpy, yes, that's the point, a little smack from me to you this morning.
If you had sent your suggestion first, I would have just rolled my eyes a bit, not written another, completely different suggestion.
Regards, P-A
ps, your suggestion is not completely wrong, just the plastic, the other works, but not optimally, but it's possible to do it that way.
ds.
It's clear there will be mixed messages when you write incorrectly. Should I then refrain from responding so that TS only gets one answer? We apparently have very different views on the purpose of forums.
The solution that TS suggested will work excellently.
The solution that TS suggested will work excellently.
Agree with Pagno about the plastic. And I very rarely agree with Daniel 109. Or at least more often with the one he is fighting against.
Could any of you then explain why condensation might occur on the outside or inside of the vapor barrier?
The risk is that there might be slightly higher moisture load around the edge of the plastic-covered area. But it's a question of 2 square meters of the entire facade, so I don't see any practical risk. However, one should adhere to the original construction technique, so if there wasn't plastic initially, it shouldn't be used later. It's unclear whether the film can be considered a vapor barrier or not.
Pannor, I am missing your reasoning as to how condensation could occur against the vapor barrier.
Can't handle it again. I've taken a break from the forum and when I come back it's still the same comments from you in all threads related to diffusion open/sealed and you never seem to take in the arguments. Look back if you want all the input again.D Daniel 109 said:
Do you mean that the moisture in the housed is kept down through permeable walls?
Of course, you should get a thorough explanation, sorry I get grumpy, but it feels like you either don't know and want to know, or you're just being difficult. I'll get back with an explanation after my morning coffee, I'm a bit nicer then.D Daniel 109 said:
Regards, P-A
As much as possible, one should always use the same building solutions as those already existing. If you have plastic in the walls, you should use plastic; if you only have a vapor barrier, it should be used. If you have fiberglass, continue with that, if it's cellulose-based insulation, continue with that. Etc.
If you are making larger changes, you can of course have someone look into changing material choices, but with any changes, new risk factors are introduced. If you use the existing ones, you have the same baseline. Provided there is nothing wrong with the existing (such as single-sealed facades or plastic-coated basement walls) of course.
If you are making larger changes, you can of course have someone look into changing material choices, but with any changes, new risk factors are introduced. If you use the existing ones, you have the same baseline. Provided there is nothing wrong with the existing (such as single-sealed facades or plastic-coated basement walls) of course.
Pagno: I'm eager to know. I'm open to gaining new knowledge. But so far, no one has presented a sensible justification.
Anders: Sure, if you build like the rest, you're confident that the new will be just as good. Neither better nor worse. If you do it any other way, you have to know what you're doing. But that's not the same as saying alternative solutions are worse.
Anders: Sure, if you build like the rest, you're confident that the new will be just as good. Neither better nor worse. If you do it any other way, you have to know what you're doing. But that's not the same as saying alternative solutions are worse.