Williamson County uses two different types of resurfacing products subdivision streets. The straight sections of roadway will receive what is called a "seal coat"and the cul-de-sacs will receive what is called a "fog seal".
A "seal coat" is a preventive maintenance surface treatment designed to preserve and extend the life of a street. It protects an aging pavement surface and seals up small cracks to keep water out of the pavement. The process starts by spraying a thin layer of liquid asphalt over the pavement. It is followed by the spreading of a thin layer of small rock. The surface is then rolled with a rubber tire roller and the street is reopened to traffic. Excess gravel is swept up by a vacuum street sweeper soon thereafter. It takes about a couple of months for the new surface to completely cure and lock the surface firmly into place with the road open to regular traffic.
The "fog seal" process received its name because it is applied on the surface of the existing pavement in the form of a fine mist. The asphalt that will be utilized is called a Tire Rubber Modified Surface Sealant (TRMSS) and is an asphalt that has been modified to be more rigid than typical asphalt and can be driven on directly. For this reason, there will not be any rock applied as part of the resurfacing. Consequently, the friction from vehicle tires will cause the fog seal to wear more quickly than the seal coat that was applied on the straight sections of streets, and cul-de-sacs will need to be resurfaced more frequently. For more information, see the Frequently Asked Questions section below.