Damp walls on extension

[noseall]

I went back and checked some of the things you guys mentioned.

1. I knocked off some plaster on one of the damp internal walls and found the brick also damp:


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2. I took some photos showing more of the outside of the building:


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The internal wall of this side of the building is where the damp goes up around 2+ meters:

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The roofing felt was overhanging, but I could not tell if it would be catching water that could then be getting inside

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3. I was thinking the damp could be being casued by the pebble dash breaching the DPM, but then I noticed that on one side of the exstention building it does not have pebble dash, yet that wall is still damp on the inside.

The wall without peble dash:

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then on the inside of the wall above it looks like this:


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-In the photo above I removed the radiator pipes boxing. I checked for leaks on the pipes but they seemed ok. Yet the wall is very damp, even though the outside of this wall has no pebble dash on it. As mentioned previously, the wall connecting the main building to the extension also has some damp at the bottom of the wall.

It's damp because it's a low end poorly built, zero cavity, zero insulation structure.

It need several thousand quid spending on it, to bring it up to snuff. Just about every façade or elevation need work doing to it.

 

[Deluks]

Do those roof tiles have enough overlap? If water was driven up underneath.....
There seems to be felt, but it's not clear what happens at the verges

 

[DM7]

is there any type of covering that could be put on the internal walls to at least keep it damp-free on the inside of the building? (as a cheaper alternative to sort the issue out for him) and if so, would the dampness underneath it cause any further damage to the extension over time?

He had originally asked me to install damp-proofing rods in the walls, but I said I wasn't sure if it was required and I didn't want him to waste money on things that wouldn't help him sort out the cause problem.