cold deck insulation board wool

Hi, hope I have posted in this in the right section of the forum.. i'm getting a loft conversion built - the builder has put 25mm of insulation above the joists and 120mm inbetween the joists in the flat roof. he's said this makes it a warm roof therefore it doesnt need any ventilation.. is...

Hi, We're cracking through our extension, I just need a little advice if that's ok. We have a 5x4m single story extension with a slightly pitched roof. I'm just wondering how to insulation it without it costing the earth with insulation board. We have EPDM, hardboard and 200mm rafters, making...