Odd bubbles flaking paint on the wall, white powder behind paint

[JohnL24]

Hello everyone,

I got an issue with a wall in a storage room. When I removed all the stuff I realized that the paint it flaking off but more oddly there was odd crumble white power behind the paint. I've attached the pictures below:

The brickwork behind is not great but what also bothers me is the white stuff on some of the other walls:

Not sure if it's related because it's not where the damp was.

Do you think my issues caused by the crack in the mortar?
Thanks

 

[JohnD]

Do you think my issues caused by the crack in the mortar?

No.

Most likely a leak.

the white bloom is efflorescence, caused when water evaporates off, and the dissolved minerals are left behind. Very common in hard-water areas.

Brush it off dry, or scrape it. Don't try to wash it off with water or this will enable it to soak back into the wall.

What was the cause of your damp, and how was it corrected? Is there a water pipe under the concrete floor?

 

[JohnL24]

There is no piping on that side and the issue is also upstairs as well in a tiny patch. I am not aware of any leaks there

 

[JohnD]

I wonder where the water comes from? post photos of the outside walls, all the way up to the gutters, and it may give some clues. is there a radiator upstairs? Or a bathroom?

 

[JohnL24]

I am wondering the same :S
Here the view of the wall from the outside I did my best to illustrate where is what, the blue blobs are the approximation areas where the efflorescence is on the inside walls:

ALSO I did some scraping in the side room, some was easy and some was not BUT what I did discover than around SOME of the issue areas there was deep holes covered up, they wen't all the way through the first layer of brick.

Behind plaster there is this cement/mortal looking layer that is very brittle and just falls off when brush by hand