Shelters can be set on compacted gravel, soil, asphalt or concrete, as long as the surface is level. On concrete, the base plates are fixed with expansion (wedge) anchors; on soil or gravel, use ground stakes or earth anchors, which can be ordered separately. Container shelters bolt or weld to the top rails of two shipping containers. Anchors, ratchets and straps are listed under Parts & Accessories.