Damp patches, bubbling paint after damp works....

[markwm]

Property: brick mid terrace, cement rendered..

I injected the exterior wall of this mid terrace property with Dry Zone over 2 years ago. Internal plaster was hacked off, treated with salt solution and then Thistle Dry-Coat(cement based) was used, then a finish coat of multi finish.

The wall was left well over a year before ANY paint was applied. Only got round to painting it say 6 months ago. Paint was soft sheen.

Last few weeks noticed some bubbling paint patches, the artic weather hasn't helped

They're isolated patches and quite high up, the worse you can clearly see as I've sanded off the bubbling paint, the wall doesn't even feel cold. On the other side on this wall is next door! Only just noticed the other two patches today. This wall is north facing and is at risk from damp as it takes a long time to dry out being.

The exterior wall is free from any cracks or defects that would allow water to penetrate. I'm convinced it's brick salts that's the problem, salt problems persist throughout these houses and it seems almost impossible to treat without removing the affected bricks.

Luckily this is the one area of the house at this level that hasn't been dry lined, reason being it's tricky to do being on the stairs. So, I need advice on a solution. My thoughts....

1. Suck it and see temporary solution....Sand off the flakey paint, apply some damp seal and paint over.

2. Board over or clad the affected area. It's only a rental so never going to be a show home. At the moment the plaster is rock solid. My only worry with this solution is that over time, will the plaster turn to mush, thus loosening any fixing used to fix the cladding...?

3. Hack off back to brick up to a level then dry line, either with treated timbers or with plaster membranes. I would use some kind of bead or dado rail to hide the join between the plaster above and the dry lining below. This being the worst case scenario.

View media item 19652

 

[Blagard]

You say you injected the exterior wall and then behind the wall is your neighbour ? That I do not understand.

Two things immediately come to mind,

The DPC if you installed one, is not working (did you do it correctly?). Or, on the party wall it can't work yet until the DPC works are completed on the neighbours side. i.e plastering and possibly the bricks on their half are not done. You can inject a 9" wall from one side (it's a pain) but you need their agreement to do their half with the risk of fluid on seaping through. If it's a half brick wall , very tricky!

Much of the rest you have posted is about covering it up which may be your only option on the party wall.

 

[markwm]

The wall where the door is, is an exterior wall. Exterior ground level is 50cm below interior ground level.

The other wall where the bad damp patch is next door. And on their side it was taken back to bare brick and then dry lined with timber I know for a fact in 2008.

The highest patch must be 1.6m or so above external ground level and below that it looks fine