I described the approach from the inside. If you insulate from the cold attic, place wind barrier paper against the boards on the cold side and then put insulation on that.
Apply a vapor barrier then. Polyetenpapp is in a way a kind of "barrier," albeit with lower vapor density. It is usually specified on various sheets/foils. It's a bit unclear if you mean to apply it from the inside or the outside or both?
If you apply double barriers, one on the cold attic and one from the inside under the inner roof, the vapor density should be higher on the inner barrier.
If you apply double barriers, one on the cold attic and one from the inside under the inner roof, the vapor density should be higher on the inner barrier.
I was thinking of only installing from the attic, when I remove the old insulation of wood shavings, I was thinking of insulating with cellulose or wood fiber. So when I remove the wood shavings, I thought of removing the old wind barrier and installing a vapor brake and then adding the new insulation. Then I also plan to increase the ventilation in the house.
Have you never seen treetex burn? In the event of a fire, you barely have time to dial the emergency number before it's too late, broke off a piece from a wall here at home and then decided that all treetex should be replaced with gypsum 😅Denniis said:
I wouldn't have put plastic in an old house, better to use a vapor barrier.
Do you want to remove the tretex for some reason? Otherwise, I think it's a bit of insulation that's not necessary to remove
It's all about minimizing the amount of water vapor in the cold attic. I don't see how it can be an advantage for more water vapor to get up there, as it does with a vapor brake.
How would moisture get trapped with proper plastic?
Are you thinking that the house is not being used and all ventilation is sealed off?
No, I've never experienced that luckilynamnbyte said:
Definitely a good input, but if you put the panel over the treetex, it should still be an improvement over the current situation, right?
I think that sofas and curtains are a bigger fire hazard?
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I think the cold attic becomes moist in late summer and wood chip insulation absorbs moisture. With a vapor retarder, it can dry in both directions instead of just upwards with plastic. I just think it feels silly to use plastic if you're not sure it's completely airtight elsewhere; if building new, I would also use plastic.K karlmb said:
There are vapor retarders for different conditions too.
Those are my thoughts, but I understand there are different opinions as it seems to be the case even among professional executors.
Here is probably a better explanation than I can write https://www.isolerproffs.se/isoleringsfakta/produktfakta/tatskikt/angbromsar/
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· Västernorrland
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That aspect of fire safety that many people emphasize is just ridiculous............Most indoor fires probably progress the same way regardless of what the wall and ceiling panels are made of. There's quite a difference between burning a loose piece of tretex compared to when it's on a wall squeezed between other materials. It might just smolder a bit if you imagine the fire starting in something electrical and then spreading.
In most houses with Tretex, it's not built-in but constitutes the outermost building layer on primarily walls. Possibly with wallpaper or fabric over it. In our house from 1950, it's the only material that makes up the interior walls besides the studs and a little woven wallpaper, meaning it won't just smolder slightly regardless of which side gets hot. Just like the wall piece we've already tested.S Stefan1972 said:
You're making it sound as if Tretex is equivalent to gypsum in the event of a fire, that it makes no difference at all and therefore it's absurd to replace it. Doubtful that is the case.
OK, but it feels quite far-fetched and actually physically impossible, that stored moisture in wood fiber would travel towards a warmer place (downward). Moisture always travels in the direction of cold. So it should just go into the air in the attic and be ventilated out there. Plastic therefore doesn't hinder evaporation, regardless of insulation material.
One does not have different opinions and beliefs about natural laws.
I haven't seen any reason to use a vapor barrier as an alternative to plastic elsewhere either, are there different conditions in walls for example? (Seriously intended question if anyone has an answer)
Plastic against the roof certainly means less moisture goes up there, but my thought then is whether more moisture goes somewhere else and causes problems there?K karlmb said:
Plastic everywhere or nowhere, and since it's difficult to get the modern tight plastic layer in an old house, you leave it alone and moderate with insulation.
My two cents.
Do a lot of craftsmen on social media and manufacturers seem to do it too?K karlmb said:
Or what am I misunderstanding in the information on the following page, for example?
https://www.isolerproffs.se/isoleringsfakta/produktfakta/tatskikt/angbromsar/