insulate from the inside

[Hus-kvarna]

Hi. Just want to make sure to do it really right. The house is clad, planking wall and tar paper inside. Inside of that is an air gap, then tongue-and-groove paneling and tretex.

Planning to lay insulation against the tar paper, wind barrier, OSB, and gypsum.
Or should the paneling be left in place, frame and insulate on that instead so there is an air gap in there. The house usually doesn't suffer from it, but maybe it's unnecessary?

 

[huggan]

The tar paper was the historical wind barrier and it should always be outside the insulation. So you should not place a wind barrier behind the OSB. The air gap has no function, so you should insulate that space.

How much were you planning to insulate? And with what?

 

[Hus-kvarna]

I was thinking of using regular gullfiber boards, about 7-10 cm or so. What I plan to have between the insulation and the OSB breathes, some form of sheeting that is not airtight but blocks wind and fiberglass. Not as tight as vapor plastic. Maybe completely unnecessary to have? Thanks for your engagement

 

[huggan]

It has no function on the inside; it is placed outside the insulation so that the air remains still within the insulation.

 

[Hus-kvarna]

As stupid as I am, I got the idea that it prevents fiberglass from leaking through small gaps etc. Skipping it then :-D

 

[Lolight]

It has no function on the inside, you have it outside the insulation to keep the air still within the insulation.

Shouldn't you always put plastic between the insulation and the board? In this case OSB?

 

[huggan]

Shouldn't you always put plastic between the insulation and the board? In this case, OSB?

No, it depends on how the house is built and whether the house is heated year-round or not. Now I'm talking about plastic.

In the post you quoted, I was talking about wind barrier paper.