We have moved to a gable end large stone terrace, dates to about 1880. Twice since we moved in, we have had extremely heavy rains, which have driven against the gable end. Both times, 2 damp patches have appeared on my son's bedroom wall, growing as the rains continued, but then dried up afterwards, leaving a very attractive stain. (by this point we had pulled off the ruffled up wallpaper - it was lilac with fairies on, so no great shame as it's my son's bedroom, we are intending to decorate it!). We had a structural man coming round for a seperate matter, he had a look and said the pointing looks ok, but as the plaster work is old, he thought it might be something to do with salts drawing moisture through? But gave me the number of a damp specialist. He came round, was in and out in minutes after saying the same. So, what to do? The first guy suggested some kind of sealant paint, or replace the plaster. The second guy suggested, well, not much really. We want to sort this before going ahread and redecorating the room. Any suggestions?
we have moved into a mid terraced property that has the same problem on one of the bedroom walls. Our builder told us it was the salts drying out and since then we have had a re-roof to stop it happening and causing serious damage. We are now at the stage of decorating and i too will be interested in any replies as to how to treat the stained and bubbled wall.
Yes, 'salts' can cause these symptoms because some of them attract moisture from the air (hygroscopic salts). Penetrating damp due to porous brickwork, poor pointing or a defect (like a cable passing through a hole, dirty walls ties, if a cavity wall) could also cause odd damp patches to occur.
You need to either replaster using a special mix of sand and cement with an additive that inhibits the passage of moisture or install a Membrane, which can be plastered or dry lined (the second version can be useful because you can incorporate insulation to make the wall warmer.
Isn't using one of those paints that seal damp areas enough once i've sanded the wall enough? We know the wall won't be getting wet again and is now dry and because it is such a small area we don't want to be charged to the hilt for a small job.
Take a look at any one of our damp projects and ring the phone number for Property Repair Systems. They give free, no obligation advice and we recommend them. They will tell you what you need to do (if anything) and will also be able to supply you with anything you need to do it with but will certainly not try to sell you anything you don't need