Vapor barrier, townhouse, wall to the neighbor

[jeppezon]

Hi, we are going to renovate our bedroom.
Today we have an uninsulated internal wall against the neighbor in the bedroom. I will insulate this, but would it be wrong if I also put a vapor barrier on my side of the wall?

 

[useless]

A vapor barrier is only needed if it's cold on the other side of the wall, so it seems quite unnecessary. The risk is that the neighbor also installs a tight vapor barrier on their side, trapping any moisture in the wall.

 

[jeppezon]

A diff barrier is only needed if it is cold on the other side of the wall, so it feels quite redundant. The risk is that the neighbor also installs a tight vapor barrier on their side, trapping any moisture in the wall.

Okay, I was thinking MAP FTX should make it airtight between me and the neighbor?

 

[useless]

Shouldn't it be different fire compartments with airtightness requirements?

 

[Matti_75]

You are thinking exactly right. It is not standard practice, but a plastic in a partition wall is completely correct. Imagine if you get negative pressure in your apartment and the neighbor is frying bacon and opens a window because it smells. They then get positive pressure in their apartment, and your negative pressure absorbs it. Only plastic film is sufficiently tight to withstand this. Also remember that you need to make the plastic properly tight against all surrounding walls, ceiling, and floor.