There are three main types of foundations: Pier, Slab and Strip. A Pier foundation is usually the cheapest and the fastest one to build. The piers are generally laid at each corner of the container. With a Slab Foundation, the weight of the container is spread over the entire slab, vs just the piers. However, because of the additional concrete used and the vast amount of space which needs excavating, slab foundations are significantly more expensive than pier foundations. A Strip foundation is just as the name implies: a strip of concrete which is laid to support the containers, is normally 1-2-foot-wide and 4-foot-deep and runs the perimeter of the container.