Lifetime recommends placing the shed on a flat structure such as a wooden foundation made of treated 2x4's and OSB board that you can pick up from your local home improvement store. The instructions show just how to build it and what materials are needed. The other recommendation is a concrete slab. The concrete slab is more pricey to erect. Some customers put it on cynderblocks, pea gravel, or other flat structures. The important thing is to make sure it is flat and drains well. If your surface isn't level (can't just eyeball it) you can run into problems with your door closing properly or having one edge of the shed off the ground an inch or so. Contact us for a copy of instructions for your shed that shows exactly how to build the wooden base or platform.