(a) No building or structure shall be erected, substantially altered, or its use changed in any zoning district without providing off street parking and or loading spaces. This off street parking and loading must be constructed of concrete or asphalt, and shall be maintained in good condition. Any alternate means of paving must be approved by the Planning and Zoning Commission by means of a variance. If any additions or alterations are made to an existing building or property which require additional parking, any and all existing parking and loading spaces must also be paved to comply with this chapter.