GaryA

Did Building control allow you to keep the 1F felt underlay or did they insist on a breathable felt?

I am converting my loft in to bedroom. I am installing PIR insulation in between the rafters and there will be 50mm clear zome above the insulation and below the felt. I will be installing a dry ventilation ridge system and slot soffit vents. Do I need to install vent tiles in between every rafter? Do I have to replace my bitumous type 1F felt with breathable felt to comply with Building regulations?

Your project sounds really interesting. I hope it is fun. I have found the most difficult aspect to be finding good sub contractors to come on board with self builds. I have been trying to find a plumber to assist me with a self build loft conversion but as yet noone has come back with a quote. I think it is reasonable to assume that as plumbers, electricians, roofers, carpenters(joiners) etc work together with local builders they dont have the same commitment to working independently on larger projects. Due to their reluctance to get involved it is essential that detailed 'building regulations' drawings are prepared so they are absolutely clear about what they have to do.