Single brick insulation and building regs

[NikkiT21]

Hi
I’ve purchased a property that is in need of some renovation (for example no gas or central heating). It has a very small, single brick extension off the kitchen which has obviously caused some damp/mould issues in the past. I was planning to add some internal insulation to it but can I do this without getting building regulations? I have a very competent builder. Surely any insulation is an improvement?

Hmmm. Rebuild it to modern standards! Or fix timber stud walls with a damp membrane. Might not cure the damp though. Internal insulation stops the wall breathing so will guarantee mould and damp. You have to make a cavity and consider how the external skin will breathe. Don’t trap in moisture or you will get further issues.

You'd need an application for that but I agree with PP - if you can afford to rebuild, do that