In my on-going quest for info WRT UFH currently being installed I came
across the following
http://www.radiantcompany.com/details/suspended.shtml
Which describes using plain ol' sand as a thermal mass for heat transfer.

My quandry now arises in that, as my thermal mass is (as suggested by
mft'r) a 16mm thin screed of 1:4 Cement/Sand. Is there any reason
shouldn't just leave the cement part out which would give better
tollerance against cracks and expansion. ALso possible improve sound
blocking properties.

TIA
PEte
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