Am I missing something, Dry lining a brick wall with door way so the block work is 100mm, 2 battens for each side is 50mm (25mm each side) and plasterboard is 25mm (12.5 ) each side so this totals 175mm with skim will be about 180mm. I am struggling to find a door liner of this size. Am I missing something I would have thought this would be a standard size?
Thanks
Thanks