Will internal wall insulation help stop condensation or make it worse

[terri]

The back addition of my 1900s mid terrace house has condensation on the walls of downstairs tiled bathroom and upstairs bedroom. I've installed humidity extractor fans, but these aren't helping. Builders have given me mixed opinions of how to remedy the issue.
Will insulating the walls make the problem worse? Any suggestions will be much appreciated.

 

[a twig]

It depends

Insulating the wall internally should mean that the surface is warmer, but it will only reduce condensation on the walls if the insulation brings the wall temperature up above the dew point.

It will also only work if you don’t have constant sources of damp / moisture present - given that it is affecting the bedroom as well as the bathroom and fans haven’t worked it suggests to me that there is a source of moisture somewhere (failed gutter etc).

 

[terri]

Thank you. That's really helpful