Garage conversion - slab depth?

[Jack07]

Hi, I'm submitting plans to convert my garage which has a concrete floor (depth unknown) into a habitable space.

The floor is currently 180mm below current kitchen floor and I would like to make this level.

Can anyone advise me on the building regs regarding the slab as I'm intending on putting 100mm of celotex which leaves 80mm of concrete OR as there is concrete already underneath can I use a different thicknesses of either material?
Also, will it require mesh to be added?

Thanks in advance
J

 

[Leofric]

80mm would be more like a reinforced screed.

 

[^woody^]

There are no regulations for the slab. You just build the levels up ensuring sufficient insulation.

But you certainly don't want to be putting concrete as a finishing layer.

 

[Leofric]

80mm thick cement sand screed reinforced with chicken wire on Visqueen 1000 separating layer/vapour barrier on 100mm insulation as required.