Damp Down Wall Join

[BenH1989]

My wife and I are in the process of stripping wall paper and we've come across a wall join that is wet.

I've searched but can't find anything that is similar.

Where two walls join in the ground floor living room, down the crease/seam is dirty and wet. Outside of this area is dry, it is purely down the join. It is dirty but not in a spot/mould kind of way.

This is on the inner joining wall of a semi-detached property at the back of the house. So basically where our central adjoining wall meets our back wall. Behind this is a conservatory

Also, above this area in the above bedroom there is a crack that is about 1mm thick and about 600mm long that runs into the floor.

If you get a tissue to it it sticks and absorbs water ever so slightly.

I've tried to attach an image. Unfortunately, i have none of the crack as we filled it and painted it until we stripped downstairs today to see this issue.

Can anybody offer any insight?

 

[bobasd]

photos of that corner from outside/the other side of the walls at ground floor and first floor levels will help.
so will a photo of the upstairs bedroom wall - even though its been made good.
and a pic of the conservatory roof where it meets the house.

the corner bead on the door reveal looks to be rusty - is that the case?

looks like you have two different types of skirting - has any damp proofing work taken place on either wall?
are the walls cavity walls?

 

[BenH1989]

Here is the full length view of downstairs (nothing on ceiling)

Here is the bedroom directly above where I’ve drawn the line for a hairline crack

Here is the conservatory where I can’t find any obvious issues

 

[BenH1989]

 

[catlad]

Cables possibly.

 

[BenH1989]

Do you think some expanding foam will solve it?

 

[bobasd]

"cables" - i dont understand?

 

[bobasd]

"expanding foam" where on what and why ?

 

[bobasd]

suddenly we have two conservatories that could be causing damp difficulties - step flashing and gable bars are in position but there's a dark looking area of brickwork lower down the wall. how that would affect your difficulties i dont know but its in the pic? dark in remedial work typically suggests damp.
both you and your neighbour will have had knock-throughs when the sliders were installed - perhaps there's been some movement or cavity trays are badly installed or missing: i dont see any weep vents near the step flashing?

on each wall plumb lines set back 300mm from the inside corner, and hack off back to brick inside these lines - this will show far more than the plaster damage we can now see.

there are still unanswered questions from my first post?