Building a cabin with wood fiber insulation. Choose vapor barrier or vapor brake on the inside?

[Tomten44]

I plan to build a cabin. I will use wood fiber insulation.
The choice is between a vapor barrier and a vapor retarder on the inside.
I want to use a vapor barrier, are there any disadvantages to using a vapor barrier instead of a vapor retarder?
The requirement is that it should be at least 5 or at least 10 times tighter on the inside, but there doesn't seem to be any upper limit.

 

[useless]

Should the cabin be warm all year round?

 

[guggen]

I plan to build a cabin. I will use wood fiber insulation. The choice is between a vapor barrier and a vapor retardant on the inside. I want to use a vapor barrier, are there any disadvantages to using a vapor barrier instead of a vapor retardant? The requirement is that it should be at least 5 or at least 10 times tighter on the inside, but there doesn't seem to be an upper limit.

You should use what the manufacturer recommends, which is normally a special retardant for the wood fiber you have chosen. If you go with a barrier, you lose the function that the insulation is intended to provide, and in that case, there's really no reason to use wood fiber.

 

[witten]

I plan to build a cabin. I will use wood fiber insulation. The choice is between a vapor barrier and a vapor retarder on the inside. I want to use a vapor barrier, are there any disadvantages to using a vapor barrier instead of a vapor retarder? The requirement is that it should be at least 5 or at least 10 times tighter on the inside, but there doesn't seem to be an upper limit.

Go with the vapor barrier as you planned, as long as the wall has an air gap on the outside it's better with a vapor barrier but both options will work.

 

[Tomten44]

Is the cabin supposed to be warm all year round?

Yes, it is meant to be warm all year round. Yes, I will live in it all year round.

 

[Tomten44]

I think I will generate more humid air than average.

 

[Tomten44]

You should use what the manufacturer recommends, which is normally a special brake for the wood fiber you have chosen. If you use a barrier, you lose the function that the insulation is intended to give you, and in that case, there is no reason to use wood fiber.

I like wood fiber insulation because it's a natural material and doesn't itch when working, but I want plastic on the inside. I don't want moisture from the inside getting into the wall at all.

 

[guggen]

I like wood fiber insulation because it is a natural material and doesn't itch when working, but I want plastic on the inside. I don't want moisture from the inside getting into the wall at all.

I have insulated with wood fiber in a house that I use as a cold storage. There, I use the recommended barrier, works perfectly, and it's fantastic to work with. But I don't understand the point of using wood fiber if you're going to have tight plastic on the inside. Mineral wool is stone/glass, a natural material just like wood and has been used for ages. Unfortunately, the price difference is still huge if you want quality on the wood fiber. Good luck!