In message , Andy Burns
writes
ARW wrote:

OK so this is a refurb and not a newbuild I am working on.

Is the whole thing anywhere near done yet?

One difficulty we discovered with a refurb and planned underfloor
heating throughout is adequate insulation over solid floor slab.

The original arrangement with wall hung radiators had 25mm polystyrene
under 22mm chipboard. The new system uses slotted polystyrene slabs with
about... 25mm of insulation below the pipes!

We could have put more under but only by losing ceiling/door height.

--
Tim Lamb