Paint bubbling - is it efflorescence?

[Adi1l]

Happy New Year to all,

Wanting to deal with some bubbling paint issues I’ve had for past year or so and hoping for some advice/pointers.

Downstairs bathroom and utility room, was painted about 20 months back but the bubbling didn’t occur until a year in.

Looking online and thinking it could be efflorescence?

Utility: The white painted wall is an internal wall under a flat room, no outside external side to impacted wall.

Bathroom: The green painted wall is an externally exposed wall under same flat roof.

Thanks for any help and assistance.

 

[JohnD]

Efflorescence is salt crystals on the surface of a wall, left behind when the water they are dissolved in evaporates.

I see none.

Show us the outside of each wall, next to its associated inside surface. Include all gutters and downpipes.

Also show the surface of the roof, especially all seams, leaks and damage.

How old is the house?

How old is the roof?

 

[Adi1l]

Thanks for the reply JohnD.

The surface of the wall had a slight fluffy residue so wasn’t sure.

Any ideas about how best to fix?

 

[Adi1l]

JohnD:

Sorry, for some reason the rest of your message, regarding pics etc, never showed first time.

I’ll get some pics of the above.

The house was built approx between 1900-1930

The problem areas are all within a side extension built approx 30 years ago.
The flat roof was constructed about 30 years ago but was repaired summer of 2022 - asphalt flat roof.

 

[Adi1l]

Outside of green wall:

Corner Green Wall:

Roof:

Outside of White Wall is my neighbours internal wall. They say they have no issues with damp on their walls.

Thanks for looking over the pics!

 

[JohnD]

The green one appears to be rainwater getting in through cracks.

The dark stains on the render are from long term rainwater spilling over.