Hi I've been getting quotes to replace my converseratory's polycarbonate roof with a solid one. Is a Buidling Regs certificate required for this? (especially if I come to move house). Some of the companies say yes and some say no Also, some of the companies want to replace the current "rafters" with stronger aluminium ones and others will just attach a wooden batten to the existing ones (the insulation and plastering is the same for both). Is using the current rafters ok? Thanks.