Hi,
I've taken some tiles off my bathroom wall and have noticed that the wall underneath looks quite damp. You can actually see tracks where water has been running. Although I've never noticed any drips as such in the kitchen below.... but I've not decorated/investigated that one yet. The room in front of that does have a problem with wall paper peeling off so I suspect its affecting the whole of the wall.
The wall is a cavity wall. External face is accrington brick - which I believe is like an engineering brick and is impervious to water. The internal wall is just standard brick (not common concrete) with a render/plaster finish. The cavity has been retrofitted with insulation - blown polystyrene I believe.
The internal wall has been patched in places and I think damp/water is running down between the old render and the internal brick and then when it meets the new patched rendering its moving to the inside on the join - does that make sense? Question is how does the damp get across to the inside wall in the first place?
Looking at the outside wall:
- the pointing is failing in a few areas. The pointing is mastic based. Why do you use mastic on engineering brick and not just sand and cement? Is that to prevent water getting through?
- the barge boards may not be providing the optimum seal between the brick wall and slate roof tiles.
I'm assuming I need to solve the source of the damp before patching the wall up? If I used a membrane to stop the damp coming through the bathroom wall it would simply move it into the room below.
How do I identify where the damp is coming from so that I can get the right repair undertaken?
thanks in advance for any help
I've taken some tiles off my bathroom wall and have noticed that the wall underneath looks quite damp. You can actually see tracks where water has been running. Although I've never noticed any drips as such in the kitchen below.... but I've not decorated/investigated that one yet. The room in front of that does have a problem with wall paper peeling off so I suspect its affecting the whole of the wall.
The wall is a cavity wall. External face is accrington brick - which I believe is like an engineering brick and is impervious to water. The internal wall is just standard brick (not common concrete) with a render/plaster finish. The cavity has been retrofitted with insulation - blown polystyrene I believe.
The internal wall has been patched in places and I think damp/water is running down between the old render and the internal brick and then when it meets the new patched rendering its moving to the inside on the join - does that make sense? Question is how does the damp get across to the inside wall in the first place?
Looking at the outside wall:
- the pointing is failing in a few areas. The pointing is mastic based. Why do you use mastic on engineering brick and not just sand and cement? Is that to prevent water getting through?
- the barge boards may not be providing the optimum seal between the brick wall and slate roof tiles.
I'm assuming I need to solve the source of the damp before patching the wall up? If I used a membrane to stop the damp coming through the bathroom wall it would simply move it into the room below.
How do I identify where the damp is coming from so that I can get the right repair undertaken?
thanks in advance for any help