"david" wrote in message
...
Polystyrene yes I cover mine with polythene sheet, don't put drainage
through, then 2 inches of sand cable laid 6 inches apart then another
2
inches then black poly over that to keep the moisture in the sand
around the
cable.

--
David Hill

Do you not put steel mesh over the cables to distribute heat.

Trevor,, Do you intend rooting into the sand etc or are you going to
stand pots etc on it.

Bell