An exterior louver blank-off panel sweats in winter
Single-skin metal can become a thermal bridge. Use an insulated blank-off detail and seal the perimeter so warm humid air cannot condense on the cold metal.
Do not use a thin raw metal sheet as a permanent exterior blank-off in a conditioned wall without checking insulation and vapor control.
Check
Look for sweating on the room-side face of the blank-off.
Check whether the panel is insulated or just one sheet of metal.
Inspect the perimeter seal and wall cavity staining.
Confirm the active/inactive louver layout on the drawings.
Use approved insulated closure material and keep drainage paths open.
Steps
Look for sweating on the room-side face of the blank-off.
Check whether the panel is insulated or just one sheet of metal.
Inspect the perimeter seal and wall cavity staining.
Confirm the active/inactive louver layout on the drawings.
Use approved insulated closure material and keep drainage paths open.
Say this to your foreman
The inactive louver panel at [location] is sweating on the interior side. It looks like a single-skin blank-off. Do you want an insulated double-wall blank-off detail before we close the wall?