For all matters related to flood-resistant design and construction, the first placement of permanent construction of a building (including a manufactured home) on a site, such as the pouring of a slab or footings, installation of pilings, or construction of columns. Permanent construction does not include land preparation (such as clearing, excavation, grading, or filling); or the installation of streets and walkways; or the excavation for a basement, footings, piers, or foundations; or the erection of temporary forms; or the installation of accessory buildings such as garages or sheds not occupied as dwelling units and not part of the main building. For a substantial improvement, the actual start of construction means the first alteration of any wall, ceiling, floor, or other structural part of the building, whether or not that alteration affects the exterior dimensions of the building.