How to tell cause of flaking paint, damp ?

[Gary111]

hi, i have a small patch of flaky paint /wallpaper near the bottom of an exterior wall , I think its plasterboarded and I think also some pipework runs through the wall.

Do I have to cut a piece of plasterboard out to see whats inside the wall ?
Or is there some other way ?
Thanks

 

[bobasd]

post pics of the inside flaking area and the outside area at ground level - mirror images.
beyond the flaking, check along the inside flaking wall at low level for any other signs of damp.
try and determine if its a Dot and Dab wall or a solid plaster wall?

 

[Gary111]

U

Thanks it’s plasterboard, there are pipes running in it though so I guess that’s favourite

 

[bobasd]

OP, if your still there?
i still dont know if its p/b or solid plaster?
the abutment of the "extension" and the old brick wall - esp the window sill - might be contributing to the damp. ie its possibly penetrating damp not rising damp?
the problem is historic - lines of injection holes in drilled bricks indicate damp problems at least say 30yrs ago - modern injections are from the 90's in the mortar beds not the bricks. fwiw: the injection holes are useless at that height above the FFL's.
there's also the smeared on pointing. i cant tell if its coloured mortar or linseed red mastic pointing?

 

[Gary111]

Thanks for coming back to me, it’s plasterboard , does seem to have pipes running in it.

The damp patch is on the newer bricks of the extension, around where it butts up to the old wall, not sure if it’s mastic or not.

I think I’ll have to open up the wall to check if it’s the pipes as I can’t see anything obvious from outside.

 

[bobasd]

sorry, i missed your first reference to p/b.
the p/b will probably be Dot and Dab.
D&D was often used to cover over damp walls.
if you removed the skirting and cut off the bottom 500mm of p/b it might reveal more. afterwards post a pic please.
be aware that damp can travel through the D&D adhesive "lumps" and show on the decorated surface.
if it was a leaking pipe then, typically, more moisture would show.