Insulating a flat roof

Ella21

HI Money savers,
I have a flat roof on an extension at the back of my house. this is very cold in Winter and I would like to have it insulated. Have had confusing messages from the guys that have given me quotes so far. I was thinking of ripping off the old felt, having kingspan insulation put on and then torch on felt over that. One guy has said to me he would put insulation between the joists and then felt over that. Does that sound OK, I thought that the insulation might go on over the plywood and then the torch on over the insulation layer ( which is what another guy who came to view the job)? Or am I completely missing the point?
Any advice on whatthe best solution for insulating a flat roof would be gratefully received.
Thanks Ella

imho

On our flat roof the insulation is between the joists,then plywood or what ever it is then the felt is on top of that. It was done a few years ago and maybe they might do it different now.
Go for the most thickest insulation you can get as its worth it in the end.

level200

I have the same problem but our flat roof is a concrete slab over the extension. What can I do?

ormus

as with all roof/ceilings, if you cannot access the void from the top, then you will have to insulate from the bottom.
be aware that the ceiling height inside the room will then be lower.