What am I looking at and how shall i fix it?

[frustin]

I'm going to decorate the hallway. The hallway was a bolt on to the main house. The main house is made from timber frame and lime render. The hallway is brick. The wall in the pictures is solid and about 1ft thick.
What am I looking at? rising damp? Dry rot?
What can i do to resolve it? dig it out and plaster?
What about refilling it? should i use lime plaster or can i use gypsum?

Same image with flash:

 

[Wayners]

Multi finish gypsum plaster used trapping moisturiser? Or vinyl paint used trapping moisturiser?

Needs to be lime plaster or lime patching filter then breathable paint

 

[frustin]

what shall i do

Multi finish gypsum plaster used trapping moisturiser? Or vinyl paint used trapping moisturiser?

Needs to be lime plaster or lime patching filter then breathable paint

what shall i do to the walls? can it be removed? with heat gun or something else?

 

[Wayners]

Any pink gypsum plaster there you can see

 

[frustin]

Any pink gypsum plaster there you can see

what do i need to do with it though? rip it off? have the whole wall replastered with lime?

 

[ree]

OP,
Before anything else, will you post a pic showing the wall surface the other side of the outside corner?
You have rising damp.

1. First you remove the skirting in pic 1 - Use a knife to cut the mitre & sealants. Examine the back of the skirting for rot.
2. Next remove all the plaster that we can see in pic1 - hack it back to bare brick.
3. Hacksaw cut the angle bead up to the same height - and replace it with a piece of plastic angle bead.
4. You may have to work on further damage around the corner after posting a pic?
5. Is the floor solid or suspended?
6. There are signs of previous work - a bit of skim over a damp area.

 

[frustin]

Before anything else, will you post a pic showing the wall surface the other side of the outside corner?

Here's a picture from the other side ad there's blistering here as well. The floor is, I think, wood laminate over concrete.

Could be rising damp from standing water externally. I moved in 3 months ago and along the outside wall to where this is, i've added a ditch outside, with ACO channelling to ensure there wont be any standing water along that face of the wall anymore. Attached is the ACO picture and blue line sort of denotes the internal wall.