Wet part of wall

[Merlin5]

Hi. I wonder if anyone can help identify a problem. I've taken some photos .







In 2012 I had lots of work done. Patio dug out and a metal slatted gully fitted for water drainage and keeping it away from the kitchen wall. Also, a sand and cement plinth along the bottom of the brickwork. In the kitchen itself, the walls were taken right back to the brickwork, sand and cemented and plastered. The hole you see in the photo is the problem. It has never dried properly and material crumbled. My builder then filled it with sand and cement again about a year ago and last night I poked around and it came away easily. What you see on the hole now is all quite solid, although in the centre to the left there's still some slimy cement. The rest of the wall either side, above and below is solid. Which makes me wonder if it's rising damp or penetration in some other way.


Looking at this picture outside,



I've circled in yellow the approximate position of the hole indoors, which is directly opposite the drainpipe. The drainpipe is new. I had the outside walls pointed and filled and don't see any holes or feel any damp on the outside wall. The drain admittedly does get clogged and I generally clear it away. But could the drain itself be the issue?

 

[catlad]

The first thing that I see is a solid wall so no cavity and I would have used insulated plaster board instead of cement/plaster and dry lined probably.

 

[wessex101]

Could be the gully. The 3 waste pipes and rainwater downpipe all seem to discharge well above the gully so you are probably getting a lot of splashing and local saturation of the brickwork. Not to mention the linear drains which probably discharge around the edge of the gully rather than into it. Difficult to tell from the photo but it looks like a right mess and very poor workmanship.

You say you had the walls "sand and cemented and plastered" which suggests it was the typical damp proofing internal render with water proofing additive. The trouble is the electrical cable feeding that socket has breached the tanking render allowing the damp from the saturated brickwork next to the gully to penetrate behind the electrical socket.

If you get the gully and waste pipes/rainwater pipe/linear drains sorted it might give the brickwork a chance to dry out. Not sure what the external rendered plinth is supposed to be doing other than trapping even more moisture in the brickwork.

 

[^woody^]

If the wall is getting damp, then the wall is the problem not the source of the damp. The ground will be damp irrespective of any gully, leaking or otherwise.

 

[Himaginn]

Is that a concrete window sill?
Check for water pooling and drainage off the sill when it's raining.

 

[wessex101]

If the wall is getting damp, then the wall is the problem not the source of the damp. The ground will be damp irrespective of any gully, leaking or otherwise.

I generally take the view that 9 inch brickwork can cope with most "normal" levels of moisture from ground water or rain etc. as the evapouration balances the damp ingress. It is when you get saturated brickwork such as a leaking gutter, prolonged driving rain or a leaking drain etc. that the balance is lost and the damp ingress wins. Rather a simplistic explanation as there are numerous factors that can also upset the balance like the rendered plinth but on the whole I find that resolving the source of the excessive dampness usually allows the wall to dry out naturally. The window sill mentioned by Himaginn above is another good example of localised saturation of the brickwork that can lead to damp ingress.

 

[Himaginn]

Should there be a drip channel along the front edge of the sill?
Is it filled in with paint?

 

[Himaginn]

Another thought/possibility. Is there normally a piece of furniture in front of that spot?
A solid 9" wall provides very little insulation and furniture against the wall can reduce the air circulation, thus causing localised condensation. Or maybe just the reduction of air flow at that spot reducing evaporation of whatever moisture does penetrate the wall.

 

[Merlin5]

Thanks for the replies, everyone. Wow, a lot of different possibilities then!

One particular positive thing coming from all your responses. Noone seems to be saying "oh, it's rising damp, you need a new DPC". I think I'd be very happy if it is nothing to do with the DPC and some simpler and hopefully less expensive way to fix whatever the problem really is. I had a DPC done when I bought the flat in 1987, so it's well past its expiry. I had Peter Cox Preservation come round last year to look at the wall but I never went ahead with their DPC. The rep of course recommended a DPC all around the back of the house including that kitchen wall. I was never sure though, I mean he never said it's 100% rising damp, it was all a bit vague.


I'm intending to sell this place but have to extend the lease first. I've instructed specialist solicitors who are going to instruct a surveyor to value my flat and cost of the lease. The surveyor bill will be between £500 and £900. Would this surveyor be able to tell me what is going on with the damp wall, would it even be in the remit along with valuing for the lease?

Regarding sills, yes, I had all new concrete sills put in, painted and new double glazed windows and double glazed UPVC kitchen door, just visible in pics.

Regarding the gully, pipes and poor workmanship, you're probably right tbh. The builders I used did a decent job in general but also left a lot to be desired! I don't really know if the pipes or drains or plinth are soaking the walls. It's annoying if they are because the whole reason I paid for the gully to be inserted and the walls pointed and fixed was to avoid water hitting the walls which it certainly was before this work was done. One thing I'm guilty of though is letting the drains block up. That drain in the picture needs clearing of stones and leaves blocking the grating.
I suppose that could be responsible for water sitting against the wall if it doesn't drain fast enough?

Regarding furniture in front, there are 3 long plastic storage boxes stacked on top of each other but about 6/7 inches in front of that wall, and have been there for quite a while.

Regarding "The trouble is the electrical cable feeding that socket has breached the tanking render allowing the damp from the saturated brickwork next to the gully to penetrate behind the electrical socket." this is a very interesting point. The fact that the mortar falling away is exactly where that cable feeds and nowhere else does make me think that the cable could be a major reason. How would one go about fixing that?

 

[theprinceofdarkness]

Looking at the outside pic, you can see a neat line of holes where a chemical DPC has been fitted. But I can't see the two holes either side of the down pipe. Have they been missed out?. Went away for a tea break and started at the wrong place.
Frank

 

[^woody^]

I generally take the view that 9 inch brickwork can cope with most "normal" levels of moisture

I'd agree for a wall above floor level, but not moisture from the ground. There would be a DPC in that wall to deal with something like a broken gulley.