DIY Doctor UK DIY Forums

I have a damp patch, now about 2ft wide and 9ins deep, on an external stonebuilt gable wall (no insulation), appearing on plasterboard (not plastered). It started about 7 years ago and is slowly getting bigger. I think it may be a bridging issue. I can't see anything outside which would have caused it.
As an interim measure can I cut the plasterboard inside and clean it out? Realise that this won't solve the damp. Any advice please would be very gratefully received. Thank you!

Hi Diana if the pointing on the stonework is good you could consider spraying with a clear sealer. These sealers do not change the appearance of the stone and i find that they do work, in my opinion it is important to only use these sealers when the wall is as dry as possible.(after a prolonged dry spell)

I would inspect the roof first as if it is the roof you are wasteing you time cutting out plaster board.

Thank you guys for your good suggestions (Fred c (clear sealant) and tilecliproman (roof), both of which I will investigate.

In the meantime a local builder has taken out a section of plasterboard with a padsaw and discovered that the old sandstone lintel of a removed fireplace was touching the plasterboard. The battens were behind the level of the lintel... He's chipped off the offending part and put damp-proofing behind the battens.
Its obviously a very old (1950's) piece of shoddy workmanship!

He's patched the plasterboard, and replastered and done a good job for a tiny price. There are excellent builders out there.