warm deck

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 all... hope you can help, I'm finding conflicting information online! I'm about to put a GRP warm flat roof on an outbuilding, I'm using 100mm PIR foil backed insulation and was wondering do I need a deck between the joists and insulation or only one above the insulation (the joists are at...

We've recently had a loft conversion done, with a warm deck roof. Inside the loft the ceiling feels cold. The builder said that's normal. A different roofer has come round and said the flat roof has definitely not been done correctly. Some pics are attached - I'd love to know your thoughts...