Spots on internal wall

[Koolpc]

Spots on mates bedroom wall. Painted, years ago.

On an internal wall. No damp in room.

Only on wall affected behind his bed.

Is that mould spores do you think?

Lack of ventilation?

House is circa 1900.

Ta

 

[kp00110]

wall behind the bed? Make sure you dont put a UV light on those

 

[DiyNutJob]

If bleach kills them then they are mould.

 

[Koolpc]

If bleach kills them then they are mould.

I will tell him to try bleach then..

 

[DiyNutJob]

Find a hidden spot and paint undiluted thick bleach on it, and wait until dry. If that has no effect at all, then it's unlikely to be live mould. The bleach might change the colour of the immediate surrounding. This is why it should done on a hidden spot.