On 6 May 2011 21:36:10 GMT, John Stumbles
wrote:

You'll need something to separate sand from ground but let
water out. The non-woven ply-something textile stuff they use on
building sites etc for various purposes is good for this: tough as nails
but water runs through it.

I was thinking of putting a base in to contain the sand but I had
thought of using 18mm ply or osb3, depending what I could find
cheaply. If it is covered when not in use, does it really need
drainage?

Thanks,
Stephen.