Notice what seemed to be a strange thing on our deck out the back.
Snow was clearing from between the gaps in the decking, and melting over
the screw heads even though it was sub-zero.

What I think is happening.
When the extension was built, ventilation channels from the suspended
wooden floors (original) were installed in the solid floor to allow
underfloor ventilation to avoid damp.
The underfloor area is above freezing.
Air is flowing under the house and warming a bit, then flowing out under
the deck at the back.
Sort of very minimal under deck heating.

Until I saw the snow and ice melting I had never considered that there
would be any real heat loss through the under floor vents.

Then again you wouldn't want the under floor area to go sub-zero.

The most of the joists are insulated to keep the ground floor rooms warm.
Perhaps I should revisit the amount of lagging on the underfloor pipework.

Cheers



Dave R



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