Damp wall (Ed.)

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Here’s the clues for my mystery. Probably a dilemma solved all day long for you experts but I appreciate your help.

Next door neighbour knocked last year. He had damp spots on his wall. His builder injected wall for rising damp. Classic 1900 Victorian in london-the type with bay windows. The damp was in his kitchen extension. Our kitchens back onto each other. Let the builder in to check my side but I had units in front.

Fast forward 8 months. Had kitchen renovated. Builders pulled down plaster covering the bricks so as to run new electrics. The wall that backs onto neighbour was SOAKED behind the plaster. Only possible solution, old chimney breast on roof. Got a bloke in to repair all the rendering and flashing up there. Looks like a good job.

Here’s the problem, builder was obviously on a time scale and refused to pause job and let bricks dry out. He rendered and painted using contract (or is it contact) trade matt. I could see within a week the wall was wet. Got a moister gauge (been stalking the forums before I posted so knew to buy one) and we’ve had some pretty wet days but the "classic" type damp patches seemed to fade. So it’s obvious what I’m about to tell you but my approach to solve the problem is out of my wheel house.

Fast forward 2 months, big damp patches dried out but I started getting bubbles in certain areas of the wall. I took pics when they first came up and pics today. Texture behind bubbles and flakes are dry. Moisture monitor says water is a lot less than when problem first happened. I’m guessing this problem is due to either residual water or builders not letting wall dry out. I haven't started using the kitchen yet so condensation isn't a factor. The brown wrapping is over a radiator which I have isolated. I wrapped it so I could spray damp block when the problem was tiny (waste of time) It's also a read herring as the problem is also away from the rad but this is the worst section. The rad isn't leaking, boiler pressure is steady with no drops

Now you have all the clues, can someone kindly tell me what I should do to stop this keep happening? Thank you, you decoration detectives you!
 

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Need pics of repairs to chimney and flashing. Is it capped/ventilated?
 
He rendered and painted using contract (or is it contact) trade matt.
when you say rendered do you literally mean that, ie cement based render as a scratch coat then multifinish over the top

or do you mean bonding plaster and then multifinish

either way over a wet wall it was the wrong thing to do -as modern gypsum plasters do not work with moisture

unfortunately I cant see a decorating solution that will work to make a permanent resolution
 
Sure thing. Here’s some before and afters
 

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His builder injected wall for rising damp.

Silicone injections do not cure leaking pipes or drains, or gutters or downpipes, or defective roofs or render, they do not fill in cracks round windows, and they do not remove earth or paving placed against walls, and they do not ventilate condensation away.

None of the actual sources of damp are repaired by injections.

Is this a chimneybreast that has been bricked up? Is it ventilated top and bottom? Is it full of wet builders rubble?
 
What are the moisture readings? What percentage?

Compare them with other solid wall readings in your property.
 
The internal kitchen wall wasn't allowed to dry out and has retained the moisture that has built up over the years of its use as a kitchen. The new render is a more efficient way of trapping it. The problem will likely persist regardless of the work done to the parapet.
 
Silicone injections do not cure leaking pipes or drains, or gutters or downpipes, or defective roofs or render, they do not fill in cracks round windows, and they do not remove earth or paving placed against walls, and they do not ventilate condensation away.

None of the actual sources of damp are repaired by injections.

Is this a chimneybreast that has been bricked up? Is it ventilated top and bottom? Is it full of wet builders rubble?Hello,
Hi. When I moved in, the chimney breast on my roof had been removed. Next doors was still there but some kind of sand cement or whatever was used to cover the area where the pots used to be. I think it was porous. This was 20 years ago. There's no air bricks at the top. Inside both mine, and my neighbours, there's no brest. It must have been removed years and years ago. All that's left is the section on my neighbours roof. So there isn't anywhere for wet rubble to be. Thank you
 
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What are the moisture readings? What percentage?

Compare them with other solid wall readings in your property.
The moisture readings were high all over the wall about a month ago. Now its non existent on the areas that doesn't have bubbling/flaky-peeling paint. the rest is still showing as having moisture but its significantly dropped.
 
when you say rendered do you literally mean that, ie cement based render as a scratch coat then multifinish over the top

or do you mean bonding plaster and then multifinish

either way over a wet wall it was the wrong thing to do -as modern gypsum plasters do not work with moisture

unfortunately I cant see a decorating solution that will work to make a permanent resolution
Yes, Im guessing it was bonding. I used the wrong terminology
 
The internal kitchen wall wasn't allowed to dry out and has retained the moisture that has built up over the years of its use as a kitchen. The new render is a more efficient way of trapping it. The problem will likely persist regardless of the work done to the parapet.
So I'm knackered? I'll never get rid of this even if the roof was fixed?
 
So I'm knackered? I'll never get rid of this even if the roof was fixed?
I don't know, what goes in comes out if its allowed to, as opposed to being trapped by cementitious plaster.
 

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