Q.: I've recently been awarded a contract to whitetop an existing asphalt parking lot in Pennsylvania. One section of the lot is 80x200 feet. Should there be an expansion joint in a section of lot this large?

A.: You'll need isolation joints (also called expansion joints) where the lot meets any building, light pedestal, or other fixed object. According to Dale Diulus of Phoenix Cement Company, however, you won't need any expansion joints in the 80x200-foot section. Contraction joints at 8- to 10-foot intervals should accommodate any slab movement caused by temperature changes and drying shrinkage. Sealing the contraction joints will help keep out dirt and debris that might restrict movement at the joint.