A tie-down plan provides the required tie-down locations for your building in order to resist wind loads. The foundation plans and tie-down plans are usually combined. Tie-downs are usually a required part of a mobile building install, and if obtaining a permit, you’ll also need to include engineering plan & calculations. Tie-downs are installed around the perimeter of the building and help stabilize the building during windy days, along with keeping the building from falling off the temporary steel pier foundation. They are a work-safe must have!