Internal wall diagnosis - mould and how to fix?

[newforestcottage]

Moved into an early 20th century cottage a few months ago. Various parts need renovating. In one ground floor room the paint was bubbling, so I took a spatula to reveal this. I’ll also be testing for moisture levels when my meter arrives tomorrow.

Would I be correct in assuming this is mould? What is the best course of action? To continue stripping the whole wall and bleach the mould? How do I determine the original cause and prevent it from reoccurring?

Walls are early cavity construction with a slate DPC below on the internal leaf.

Thank you for all advice you can offer

 

[noseall]

View attachment 305153

Moved into an early 20th century cottage a few months ago. Various parts need renovating. In one ground floor room the paint was bubbling, so I took a spatula to reveal this. I’ll also be testing for moisture levels when my meter arrives tomorrow.

Would I be correct in assuming this is mould? What is the best course of action? To continue stripping the whole wall and bleach the mould? How do I determine the original cause and prevent it from reoccurring?

Walls are early cavity construction with a slate DPC below on the internal leaf.

Thank you for all advice you can offer

Doesn't look like (black-spot) mould to me.

 

[newforestcottage]

Are there reasons why a blue speckled pattern would be expected or normal? Can’t imagine it’s the plaster itself?

 

[noseall]

Are there reasons why a blue speckled pattern would be expected or normal? Can’t imagine it’s the plaster itself?

Black spot mould forms in a distinct pattern, i.e. settling on the surface of condensed water. It usually manifests from an internal corner or abutment outward. Seems odd that there was no spotting on the paint itself...?

 

[newforestcottage]

Yes, the paint itself is generally fine. There is some discolouration which suggested damp or condensation (which hasn’t changed in area in 4 months).

Using a mould remover on a test area does appear to have reduced it a bit.