by rap12 »
Tue Nov 05, 2013 3:23 pm
You have an internal wall thats been dot & dabbed on both sides of the wall and is now showing "damp" spots at the dab locations?
Unfortunately, if there is damp in that wall then the moisture and salts will penetrate through the fixing dabs no matter how much ventilation is introduced behind the p/board.
Setting plumbed & plugged battens on narrow strips of dpc suggests itself as the answer.
There are remedial p/board adhesives available if you search google - they claim to deter damp and salts.
Some claim, that instead of using adhesive, that rapid foam will do the trick. I dont know, but i doubt it.
Why not try what you propose on one side of the wall only (simply vent - top & bottom) and then watch and wait? Warm air rises, by the way.
Was this an original interior wall, not a shippen wall?