H
hutch6447
Good info, also as I am just used to surface laying this whole chase cutting is a bit of a new experience, now the chases has capping in it and has to be deep enough to accommodate it, the metal back boxes are 35mm deep so sometimes do you have to chase into the brickwork itself as sometimes you must o deeper than render? Take it this is the reason for vertically 1/3 wall thickness horizontally 1/6 no deeper than.