I've got a flat roof ( wooden, sealed with tar and then roofing iron on top of that ) with a 30 cm gap between the ceiling. Not really enough for someone to crawl in unless skinny.
There's no insulation there at present. The lowest the temperature gets is 0 Centigrade.
I've read on various sites that you need a gap between the roof and any insulation, about 30 cm. But that would mean I can't insulate.
Is the purpose of the gap to prevent condensation of the insulation material against the roof? Is that a concern when I have a wooden roof?
Could I use blown wool? That is said to both absorb and release moisture.
I don't have any down lighting ( which can be a hazard if covered with insulation ). Recommended R value for this area for the ceiling is 2.9 metric ( US R of 16.5 )