Rising damp

[Harry Bloomfield]

House is built on a slab, on clay, had damp injection 40 plus years ago, and cavity cleaned out. All fine, no problems except one small, out of the way area, which is an internal brick wall. The wall forms a T with the short upper arms of the T, being the inner cavity wall. The wall is around 2 1/2 foot long, coming a right angle out from the cavity wall. On one side of the wall is the understair cupboard, the other is at the back of the downstairs toilet. The only obvious sign of the damp, is that the plaster bulges out at each side of the wall, for a couple of inches in height. There is skirting board at each side, with no sign of rot or damage to the skirting. No indication of any damp, on the adjoining cavity outside wall.

It has been like that for several years, not getting worse. What is the best way to fix it please?

 

[foxhole]

Could be slow leak from toilet , damp injection would prevent it drying.

 

[Harry Bloomfield]

Could be slow leak from toilet , damp injection would prevent it drying.

No, all around the toilet is perfectly dry. I know the outside walls were all injected, not sure whether the inner ones would be. I also wondered if the damp course might have been bridged by the plaster, behind the skirting(s).

 

[Koolpc]

Contaminated plaster? Hack it off and put fresh on in that spot after letting it dry out?

 

[Harry Bloomfield]

Contaminated plaster? Hack it off and put fresh on in that spot after letting it dry out?

It's the same on both sides of the wall.

 

[blup]

Is the T wall built on earth, or absent its own damp proofing, such that the damp bridges

 

[ree]

OP,
Sounds like a very big job that deserves visits from the Damp & Timber companies.
In the meantime why not post lots of pics of the inside and the outside - post as many as possible?
Plastering both sides of the wall seems to be another option.
Your posting history suggests that you are the kind of poster that deserves as much help as possible.

 

[foxhole]

No, all around the toilet is perfectly dry. I know the outside walls were all injected, not sure whether the inner ones would be. I also wondered if the damp course might have been bridged by the plaster, behind the skirting(s).

Quite possible For toilet to leak from soil pipe without any visible signs in room .

 

[Harry Bloomfield]

Is the T wall built on earth, or absent its own damp proofing, such that the damp bridges

That I don't know. It is clay round here, so my assumption is the house is built on a raft. Lift the floor coverings, and there is a layer of black compound to be seen. Drill, through that, and there is concrete.

 

[Harry Bloomfield]

Quite possible For toilet to leak from soil pipe without any visible signs in room .

The soil pipe is set in the floor, with the toilet mounted directly on top. There are no leaks from the cistern or pipework.

 

[foxhole]

The soil pipe is set in the floor, with the toilet mounted directly on top. There are no leaks from the cistern or pipework.

So you can’t see if soil pipe is cracked then .

 

[Nige F]

OP,
Sounds like a very big job that deserves visits from the Damp & Timber companies.

Are you on commission ? You missed the tarmac in post #9

 

[Harry Bloomfield]

So you can’t see if soil pipe is cracked then .

I've had the toilet out in the past, there were no signs then, of the soil pipe being cracked, though I had the damp issue.

 

[ree]

OP,
You really need the Damp companies out there as soon as possible.
A thorough, full house damp survey will do your problems no end of good.

 

[JohnD]

But not anyone who sells silicone injections.