Floor insulation options

[giggadygoo]

Hi All,

I am converting my garage into a living space (permitted development).

The current floor is an un-insulated concrete slab with a 2" slope

My current plan is as follows:

Damp proof membrane directly on the slab.
Then 50mm foil backed Celotex.
Then a screed to level the floor, 1" at thinnest to 3" at thickest point.
Then 1" battens and 1" Celotex
Then floor boards

I understand that regs call for 1200mm of Celotex but their is no way I can raise the floor that much.I have seen multifoil but this is controversial in its effectiveness and also needs an air gap on either side so I will not save much space. Another option is foil bubble insulation. Is their a thinner way that I can meet the required insulation amount?

Any thoughts and advise would be greatly appreciated.

NB: This conversion is out of necessity as I need to rent out my bedroom if I am to be able to pay the mortgage (thank you con-dems!). I am an amateur and will do as much of the work as possible myself. Please - no lectures about how I should work to regs - I an trying to do this but it is not possible with Celotex - hence the post!
Thanks,

Andy

 

[noseall]

Building control will not insist that you fit the max recommended depth of insulation, rather they will expect you to fit what is practical.

On our last conversion for instance, we didn't fit any.

I would try and achieve a (min) 2" screed at the thinnest point and insulate accordingly.

 

[giggadygoo]

brilliant thanks.