The message
from The Natural Philosopher contains these words:

You MUST insulate the floor though, or it will be bearer 400W/sq meter,
with you providing a nice little soil heater for the worms..

Not to mention being illegal. Though some of the recent rules are rather
daft, the one insisting on proper insulation under solid floors makes
sense. I've got 4" under the conservatory floor.

--
Skipweasel
Pay no attention to that man behind the curtain.