Greenhouse base

[hammer]

i have been asked to build a base for a 6' x 4' greenhouse. i was going to use 6 2ft x 2ft slabs. is it ok to dig out to 90mm and bed the slabs on sharp sand or do i need to have a sub base, then sand.

[pepperday]

personally i hate gardening. But depending on ground conditions and how long the green house is going to be there, level & compact slap on the slabs. If however its for a paying client then follow McC's advise on the website.
I always remember my mother's green house, only wanted it in temp location, couple months, waiting for another part of the garden to be prepared, ended up 15yrs same location, never moved / sank.