I've moved an old Victorian door from one stud wall to another in a house in the UK. Rather than faff about trying to patch repair the lath and plaster walls, I've just ripped them back to the timber frames. I have 12.5mm acoustic ply to affix. I'll get this skim coated, which I understand will only be 2-3mm thick (say 2.5mm for ease of the calculations that follow). The old Victorian door liner sits 25mm proud of the studs. I'll also reinstate the old 20mm thick architrave. 12.5mm plasterboard + 2.5mm plaster = 15mm so the liner would still be 10mm proud of this. My initial thought was just to pack a strip behind the architrave but then the frame (architrave) would appear to be 30mm deep (20mm architrave + 10mm packing strip)... which I think would look chunky and out of place. I'd have the same issue with the skirting. Is the best solution to use 9mm ply to pack out all the timber studs and noggins? If so, what type of ply (structural, non-structural, marine). This is on the bedroom side of what will be an ensuite bathroom. I'll also need to pack out the other side but using tile backer board in place of the acoustic plasterboard so same question for that. Thanks in advance!
