I am in the process of turning an existing garage into a habitable room.
The garage currently has a single skin brick/ block external wall, this will be timber lined and insulated on the inside face. My query is, should I fix a breather membrane directly onto the inside face of the existing brick wall before fixing the timber framing, or is this not necessary? An alternative is to apply a liquid waterproof coating to the inside face. Or nothing.
I would have thought so.
I would go with: membrane, timber frame, kingspan in the frame (leaving a gap between the kingspan and the wall/membrane) then plasterboard.
Make sure you foam every gap between the kingspan and the frame before plasterboarding.
Andy, dpc, damp proof course, auto correct!. I ground out the mortar on the inside of the wall, slipped in a double width dpc and mortared it in. I then then brought the polythene down and folded the dpc up over the polythene. That way any water that penetrated the brick ran down to the dpc and hopefully back out rather than pooling on the floor.