It is recommended that 3"-4" of crushed stone or gravel be used as the base (with or without a wood perimeter). The base should be 12" larger than building on all four sides. Please make sure that the base level; we are not responsible for structural problems if the base is not level. Blocks can be used, but is not recommended as a good option. We are not responsible for yard and/or driveway damage. It is your responsibility to decide if conditions are suitable for delivery.