2 X Research source For the front, cut 4 boards that are 12 feet (3.7 m) high. I personally used wood in building a backyard shed as I already have some materials available. Most on-grade shed foundations are easier to build and don't need a lot of special tools or expertise. For slightly larger sheds it can be positioned on some crushed stones or railway sleepers, you may decide to use concrete blocks or paving slabs.