New floor for underfloor heating

8 Jul 2009
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United Kingdom

I am replacing my existing old concrete floors throughout the house. The original floors had no DPM or hardcore just cement on soil.

I am planning to replace with a new floor and underfloor heating.
I have removed all the existing concrete but I now need to know how far I should dig down below the existing floor to accommodate all the required materials

At the moment I am planning to use

65mm Screed
100mm Celotex insulation (with heating pipes clipped)
100mm concrete slab
1200 gauge DPM
20mm compacted sand
50mm compacted hardcore

Which means i need to dig down 335mm below the original finished floor level.

Does this sound about right, i am a little unsure what the minimum requirements are for sand/hardcore etc for building regs.

Any advice would be appreciated.

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