Help solve the damp issue!

[Hairy Tofu]

Hi,

Recently purchased a property after falling in love with the size, location. The surveyor noted previous damp stains on the 1st floor landing so I got a damp specialist in. The specialist also noted damp stains to the 1st floor landing, which he said could be related to the parapet wall which is directly above this area. He said because of the angle and concrete slab at the end, the water is simply running down the house wall and causing penetrative damp.

I recently had the house painted, I scraped back the area of damp damage and scraped the salts off that had accumulated. I did not treat the area. I had a period of decorating and the night after decorating, there was extreme rain. I came into the house to find the wall (in the exact same area, with exact same position and size) completely soaked. The fresh paint had peeled off and again the same salt marks are visible

I have recently paid to have the parapet wall coated in a felt, which the specialist said would allow the water to flow into the guttering rather down my walls, some flaunching on chimney fixed and other bits and bobs. However, the roofer also mentioned he is concerned about the colouring and staining of the render and that there could be potential damage to the render itself which is allowing the water in. I’m lost and I can’t keep paying for works that people “think” is the issue. It’s weird how it doesn’t start from the top of the wall and suddenly appears halfway down the middle as seen in the pictures.

What should I do? Any recommendations? My thoughts are to take the wall back to brick, treat the salts and then replaster and repaint the area. See if the issue comes back. Maybe due to the salts left behind after cleaning them, it appears as damp but they are just soaking up moisture from the air? When I touch the wall everyday it’s not appearing wet, infact it’s bone dry and just “stained” with visible salt deposit. Even after rainfall it doesn’t appear wet. It’s very confusing as the water must be coming from somewhere? I notice cracks in neighbours render on the property boundary and there is staining on my internal wall at the corners the walls would meet (see pics).

I have attached some pictures of the wall and the render outside.

 

[Wayners]

Is that end to your neighbours gutter ok?
Wall looks cut back.

Do you have a cavity wall?
What about camera pushed inside cavity to look?

 

[Hairy Tofu]

Is that end to your neighbours gutter ok?
Wall looks cut back.

Do you have a cavity wall?
What about camera pushed inside cavity to look?

I am unsure what you mean by the neighbours gutter/wall looking cut back?

I’m not sure if I have a cavity wall - I’ve just purchased!

The roofer has finished works and concluded there is absolutely nothing untoward going on in my roof. He can’t suggest anymore remedial works. My guttering it fine, no loose tiles, no damage to render that he can see. So I’m now looking at other causes - for example the neighbour property because the wall that is getting damp is also shared at the corner with the neighbour and some damp is coming from the corners

 

[foxhole]

Water will have soaked behind render and probably blown it trapping moisture.Does it sound hollow when tapped or any movement?
Even with any problem solved you are looking at summer before it dries internally or even longer , salts can leech out for many months .
Should be lead at base of wall directing flow to gutters?
Way too early to decorate .

 

[Old Salt]

I would have a look at that corner area when is raining hard.