Vapor barrier in 70s house?

[Lille farbrorn]

Renovating the interior wall in the kitchen, and had to get rid of the existing tar paper. The house is additionally insulated, and I see no signs of moisture damage or moisture at all in the framework after taking it down. The paper I removed cannot be replaced with new paper, and the smell improved after it was gone. However, I have two considerations now that I'm installing a new interior wall:

- Should I add a vapor barrier to replace the tar paper I removed? I will be adding OSB and drywall which reduces vapor permeability (it was particle board before), and there is an existing vapor barrier in the form of tar paper against the interior wall.

- If I should add a vapor barrier to the interior wall, which one should I use? It's a jungle. I have a Mataki Halotex D20 (Halotex D50 Vapor Barrier - 25x2.7m - Mataki) that I purchased, but D50 is the tighter one. And what function would the vapor barrier serve when there is already a vapor barrier/barrier in the form of tar paper against the exterior wall.

Attaching an image of the cross-section of the house wall (before/after).

 

[Mats-S]

"Don't fix what ain't broken"!

The house is additionally insulated, and I see that there are no signs of moisture damage or moisture at all in the framework after taking it down.

So, that solution works excellently, why risk it by incorporating a denser vapor barrier that probably won't add anything in your case. The OSB board and drywall are sufficient; plastic is always a risk factor in renovations of older houses.

Your current solution with tar paper has worked for 50 years, continue with it

 

[Lille farbrorn]

"Don't fix what ain't broken"!

So, that solution works excellently, why risk it by involving a denser vapor barrier, which probably doesn't add anything in your case. The OSB board and gypsum are sufficient; plastic is always a risk factor when renovating older houses.

Your current solution with tar paper has worked for 50 years, continue with that

I completely agree. I don't want to add a vapor barrier if it's not needed - the main question is whether the old tar paper I've removed should be replaced with a vapor barrier or if I can go with OSB + gypsum directly against the inner wall, or if a vapor barrier is needed... I have _not_ planned to add a vapor barrier.

 

[Mats-S]

I completely agree. I don't want to add a vapor barrier if it's not needed - the question is mostly whether the old tar paper I've removed should be replaced with a vapor barrier, or if I can proceed with OSB + drywall directly against the inner wall, or if a vapor barrier is needed... I have _not_ planned to add a vapor barrier

I would go with that solution, OSB + drywall works perfectly to replace the previous tar paper