Open areas used for storage or for parking or loading of vehicles having a rated capacity greater than sixteen thousand (16,000) pounds manufacturer’ s gross weight rating as defined in the State Vehicle Code, shall be enclosed by a solid wall or fence not less than six feet in height, with solid exit and entrance gates. In no case shall any material be stacked or stored so as to exceed the height of the fence. All other open portions of the lot or building site shall have adequate grading and drainage, and shall be continuously maintained in an all-weather dust-free condition by suitable landscaping with trees, shrubs, or planted ground cover, or by paving. Except as a temporary use regulated by Section  17.52.480, use of a mobilehome is not permitted. (Prior gen. code § 8-51.10)