Hi im after a rough estimate for a mid terraced 2 bed new loft floor to have to big beams installed to hang new joist between existing. To regs. Will a builder or joiner know what the regs should be. I plan on then doing as much of the rest my self. My brother a sparky.the Insulation and stud wall to the regs ive found on internet. To leave 50 mm air flow between roof and walls.
Also my roof tiles have no membrane under. Can i leave 50 mm gap between tiles and foil back coltex board. To alow roof to breath. Some articles say its better not to have a membrane under tiles. So the wood breaths better or is there any other insulation i can use. I don't want to have the roof redone its all fine.
