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Hi all,

I am just about to start laying oak planks on a suspended wooden
floor. At the moment the central heating pipework is attached to the
joists, with about 10mm from the pipework to the underside of the
flooring planks on top (clipped along the joist, not running across
joists). The supplier of the oak planks has told me that this is too
close, and the oak planks will suffer from localised heating, leading
to eventual warping. I suggested putting Kingspan insulation in the
gap, but they weren't happy with that either, saying that the
temperature at the underside of the planks mustn't exceed 27degC, and
10mm insulation is unlikely to be sufficient, but they can't tell me
how much would be sufficient. Now I can easily lower the pipes and
increase the insulation thickness, but how far should I go? Given
Kinspan's insulation figures, could I work out the temperature drop in
any way?

At the same time as doing this job, I am insulating between the joists
with 100mm Kingspan, so it makes sense to run the pipework within the
Kingspan, rather than dropping the pipework down under the joists, and
lagging them separately, but will, say, 50mm of Kingspan be enough to
keep the temperature down sufficiently?

Incidentally, I could try an experiment with different thickness of
insulation, and measuring the temperature after running the heating
for a while, but I'm fitting new radiators at the moment so can't run
the system to do this experiment.

It would be more sensible to use pipe insulation around the pipes as that
will reduce the amount of heat getting into the void rather than just keep
it away from the top.

You can get stuff that is 3" thick.

BTW what happens in the summer when its 30C on the floor?