Broadback wrote in message ...
Any tips on estimating tonnage of topsoil required for given volume?

Call it a tonne and a half per cubic metre. It varies, of course, but
that's pretty standard. Best to stick to metric throughout, to avoid
confusion.

(Not part of the question, and of course you know more about your
garden than I do, but actually people don't always need topsoil as
badly as they think. Sometimes a really forbidding site turns out to
need no more than a bit of heavy clearing and ordinary soil
improvement measures. If heavy clearing is necessary for rubble etc,
topsoil isn't always the cure. If you're not certain about this, we
like talking about that here!)

Mike.