Extension not properly insulated? Next to extension???

[123Holly]

After a little advice.
We bought a house last year (scotland) and over the winter the room that sits next to the garage is absolutely freezing. It does not have sufficient radiators which we thought was the main problem but today when I’m was in the garage I noticed that the side that the extension is on is only plasterboard instead of the breeze blocks like on the opposite side.
My husband went inside and we could literally talk to each other through it.
At the tine of extension they had a new boiler installed in the garage and moved some pipe work so the dry walll looks quite fresh.
Question...is this against building regs? What can I do to fix it?
I feel so stupid for not even realising until now.
We had to use plug in heaters all winter.

If it is a stud work plasterboard wall you can have the board taken off one side and the void packed with insulation, then reboarded and skimmed.

You could also have an extra layer of insulation added to one side, but this would make it thicker.

Plasterboard is non-flammable. Foam insulating board is not so I would only use it encased in a plasterboard wall. Your building regulations would probably require that anyway.

Mineral wool insulation is non-flammable but has to be thicker, 100mm would probably be suitable. It is available in a heavier, sound-reducing grade.

Also look at the ceiling insulation. You lose a lot more heat through a roof due to convection and size.

Thanks for that!
I will cut a little hole in to see what it if any insulation is already in there. And hopefully it can be improved upon.
It’s kind of like a half job at starting a conversion as the ceiling has also been plaster boarded with a light.
There’s a house the same style as ours a few doors down so I’m tempted to go and ask them what theirs is like. They have had the same extension to the side.

Do you mean that you’re using a partial garage conversion as a room? There are definitely, quite strict, building regs about this and the lack of them should have come up through your solicitor. Is the floor a different height to the garage?