Loft insulatio

Thanks for that noseall.
You live and learn as they say.

we can all of us live, 'tis only the wise ones that are prepared to learn.

SPoke to my building regs chap and as Noseall says, to meet Regs you need to ensure a 50mm gap between celotex and tiles

Example:
My rafters are 100mm so i add 30mm batten down them. Cut in the 70mm Celotex flush with the front of the battens, gives me my 50mm air gap between celotex and tiles (not felt).

Then cross batten with further 25/30mm batten and then plasterboard with foilback.

Hey presto.

There are many different combinations of insulaton between and underneath that will fulfil BR requirements but whether you install between the rafters and add battens to increase rafter depth or use more insulaton underneath the rafters you are gonna lose headroom in the loft. I guess the solution depends on whether you are using this space as a proper room and need BR approval for it or if you're just wanting to make the loft space a bit nicer and a bit warmer. If you're wanting to use it as a proper room then i'm assuming you'll be wanting stairs up there and if you've only got around 5ft5in headroom at the moment you don't stand a chance of meeting building regs without lowering the ceilings below as you need at least 2m headroom over the top stair.

People often think that converting the loft will be a quick and easy way to add more room to their house but in many cases they can be difficult to acheive.