No materials, supplies, equipment, or products shall be stored or permitted to remain on any portion of the properties outside a permanent structure without prior written approval of the Planning Commission. Outdoor storage (that is, materials, supplies, equipment, waste containers) shall be permitted only where screened from view by a permanent wall, mounding or other appropriate screen and confined to approved locations. This provision shall not be applicable to the materials, equipment and supplies stored in relation to and as or part of the construction of permanent structures upon a parcel, which materials, equipment and supplies shall be removed immediately upon completion of construction.