Pallet base for greenhouse?

Looking for a quick bit of advice - I have the frame and glass for a greenhouse disassembled on my plot but no base. I have some slabs and was thinking of mounting a framework of heat treated pallets on top - use some wood preserver and bolt them together with a weed membrane underneath.

I just can't get ahold of affordable sleepers unfortunately.

Has anyone tried it? Can it work? And if so any tips?