Im about to to arrange and sand/cement skim to inside of externals walls (as recommended by airtightness contract to make walls airtight). After this, the electrician will soon start first fix on the walls and Im struggling with a key question regarding installing the 50mm insulated slabs (37+12 .55mm plasterboard) that will be done after the electricians fix.
Elsewhere in the forum (and in the part L regs), the suggestion is to use a 50mm by 25mm baton around the perimiter of the wall and openings and screw the boards to the batons (I assume here the baton will need to be every 2 feet across the wall to ensure a good fix on the board) (not mentioned in the regs). Im also wondering whether these batons need to be treated at all ?
This approach leaves an 25mm airgap between the board and the wall which I also understand means that the electrician will not have to chase for wires as he can use the 25mm gap as a service cavity. There is 60mm xtratherm in the cavity.
However, I spoke to the insulation people and they said it simply depends on whether you mechanically fix the boards or whether you simply glue them to the wall. However, as i see it If the glue method is used, then there is no air gap and this also means the walls need to be chased.
Im a complete novice managing direct labour and would like to do this properly.
Any help would be appreciated.