Hardcore for greenhouse base? (Moved from Projects)

[BlueGirl]

I've cleared an area of garden to build a 10'x12' base for a 6'x8' greenhouse. About half of the cleared area has a reasonably level layer of brick, which was the floor of the shed that was there previously. The rest is compacted soil. I'm thinking of laying concrete slabs on a dry mix of sand and cement. Will I be able to lay the sand and cement directly onto what is there already or would I be better adding a layer of hardcore first? Either way, what depth should the sand and cement be?
Any help would be much appreciated.
Cheers
BlueGirl

 

[freddiemercurystwin]

http://www.pavingexpert.com/layflag1.htm

 

[BlueGirl]

Thanks for that, it's really useful. Still unsure whether I need to bother using any sort of sub-base is required. I'm thinking I can maybe get away without it provided the bedding layer is a decent depth. Anyone see any issue with the fact that half the area is brick and the other is just compacted soil?
BlueGirl

 

[r896neo]

I would be relatively happy to go ahead and lay straight onto the ground assuming your using a 50mm bed of 6:1 or stronger and as long as its been compacted. Personally i always prefer to throw down even an inch of hardcore as trying to compact bare soil doesnt really work, your better off trying to ram hardcore/ gravel into it with a vibrating plate to achieve compaction.

If possible try and have a joint in the paving where the base material changes as if you don't redo the whole thing you will get a little settlement in the medium-long term as the two sub-bases settle differently which may crack the paving or if not will certainly crack the joints. (mainly superficial aesthetic crack)