Double Stud Wall in Walk-out Basement
Hello All! I have recently inspected a house that has had a basement renovation completed. The basement was finished with a secondary wall built adjacent to the original foundation/pony wall.
The foundation wall is covered in EPS insulation and appears well detailed with tape and spray foam, as well as being well sealed to the bottom plate of the interior wall and pony wall. The wood framed pony wall has Roxul batt insulation in it. The secondary 2×4 interior wall has nothing in it.
The problem is the original 2×6 pony wall does not have a vapour barrier installed over it. I measured for wood moisture content on the original sheathing (1×8 fir) and its at the red flag zone of about 18% in many locations. The original wall being stucco clad with 1×8 sheathing and ashpalt paper is quite air leaky.
I’m not entirely sure what to suggest to the home owner’s except a complete tear down of the secondary wall or at least a partial tear down in order to install a vapour retarder/air barrier on the original 2×6 wall. Along with drywall to help support the retarder (as well as fire protection) in this leaky wall…Any other ideas? Is there an vapour retarder/air barrier that can be used that does not need the addition of drywall? I suppose one can use plywood…
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