Ground cover for garden

[Fred]

Fred,

From memory a tonne covers about 3m squared but my memory is getting fuzzy and it's also going to depend on how thickly you want to cover the membrane.     sorry - message from the department of the bleedin' obvious.

Not sure if that helps, so if I want it say around 10cm depth I would need one tonne plus a couple of wheelbarrows full or a few decent size buckets.  

Thanks anyway, I better go and get some more black coffee before trying to work it out.