Peter Parry wrote:
On Mon, 13 Jul 2009 21:09:13 +0100, "BruceB" wrote:

I am laying wet underfloor heating in a mill conversion. Upstairs the pipes
are laid on 30mm celotex between the joists. There is then an infill of
dry(damp)mix around the pipes up to the top of the joists. 20mm T&G oak is
then due to be laid on top of that. I was wondering whether the efficiency
of heat transfer would be improved by some sort of heat transfer paste
between the drymix and the oak.

Our underfloor system has clip on aluminium heat spreaders on the
upstairs pipes. They rest on the joists with the channel for the pipe
below them. I wouldn't expect any form of heat transfer paste to make
any difference, the rate of change of temperature isn't exactly fast.

Exactly. Microconvection to the boards is as good a way to spread the
heat as any.