Mini Storage Building Foundations
Mini storage foundations are commonly poured to the size of the building plus 1 1/2" around on each side for a notch. For instance, the foundation for a 20' x 100' mini storage building is poured to 20' 3" x 100' 3". The notch is 1 1/2" lower than the finished floor, which helps prevent water from seeping into the mini storage unit. The mini storage roll up door closes in front of the notch, flush with the threshold. The threshold is typically 9 1/2" deep. The concrete floor is commonly 4" thick with a thickened foundation edge for support.
The building supplier is not responsible for foundation design or material selection. A foundation engineer will have to design the foundation for your area if required. Your actual foundation design will vary depending on your location, soil conditions and local building codes. Foundation design cost is not included in the building material pricing unless specifically listed.