We are retaining a double brick, no cavity wall in our renovation. At the moment it is like this on the inside -
The other side is painted. It is a boundary wall & we only have about 45mm to use on the other side. It faces north-east & gets a lot of sun, we also need acoustic insulation.
Is there a way we could insulate the wall on the outside instead of taking up space on the inside? What materials could we use, to be sealed with something like Acratex?