Advice on building a greenhouse please!

[Peggy Sue]

OK I can't wait another winter without a greenhouse, everyone down the allotment has huge plants from their greenhouses and we have tiny ones and windowsill creeking under the weight!
The garden is quite small but we think we can do 6' x 6' (which is the statutory 2' bigger than we think we need!). There are some bargins to be had out there now so found a good deal...but...
the only thing holding us up the the constant indecision about the base.

The 'site' is currently flatish grass. We don't intend planting in the soil, it's mainly for warm shelf space to bring on plants for the allotment until they are plantable size/frost danger is gone.
It will be a big task to lay a concrete base (the ground is rock hard clay right now). Can we simply anchor the base to the soil?
If thats a really silly idea what will be the simplist (least backbreaking/timeconsuming/money consuming) If I lay slabs do they have to be concreted in or will it work of they are on a bed of sand, therby helping drainage?

Hopefully someone out there has done this!

[pumpy]

Hi Peggy Sue, our greenhouse is fixed down to slabs, which were just laid down on a area of levelled lawn. However, it was supplied with tent-peg type skewers to fix it direct to the ground. However it is recommended that these skewer thingys are set in concrete. I s'pose it all depends on how sheltered your garden is. Take a tip from me & don't site the GH on top of an ants nest!

[Peggy Sue]

Take a tip from me & don't site the GH on top of an ants nest!

My mind boggles
I'll bear all that in mind Pumpy

[Peggy Sue]

Ooo this is more advice that I've squeezed out of everyone round here in months!
I'm getting a greenhouse with a base, so I shouldn't need the wood I guess? Sinking it in the ground I hadn't thought of, will run that by the OH (has to get seal of approval you understand!).
I'd thought I would just throw a few flagstones down, can usually pick them up on freecycle, and bolt it to them, I'm just not sure if that will be a problem?

Thanks for the advice guys, any other thoughts for the bag welcome!