Subgrade preparation, pavement thickness, and drainage are crucial components in the construction of asphalt surfaces. In this discussion, we will differentiate between residential asphalt driveways and commercial asphalt parking lots. 

THE FOUNDATION

Residential

For a driveway, the foundation begins with the subgrade, which should be smooth, stable, and uniformly shaped. It is essential to use a properly compacted granular base aggregate of 6-8 inches on top of the subgrade.

Commercial

The thickness of asphalt in a parking lot is largely determined by the volume and type of traffic it will experience. For typical commercial applications, a dense-graded aggregate layer of approximately 8 inches is standard. On this base, we recommend two layers of asphalt, each 1.5 inches thick, with the first binder layer consisting of larger stones. For areas subjected to heavy traffic, such as trucks or loading docks, a 2-inch binder layer is advisable.

ASPHALT THICKNESS

Residential

Asphalt driveways should have a minimum thickness of 2 inches, with 3 inches being the typical compacted depth.

Commercial

In commercial settings, the final layer of a parking lot, placed over the binder layer, should consist of finer stones and measure 1.5 inches thick, bringing the total to 3 inches. For heavy-duty applications, a 2-inch finish layer on top of a 2-inch binder is recommended, resulting in a total thickness of 4 inches.

Light Duty vs. Heavy Duty Parking Lots

For light-duty commercial lots, a compacted layer of hot mix asphalt about 4 inches thick is recommended on the subgrade. In contrast, heavy-duty commercial lots should have a layer of approximately 7.5 inches of hot mix asphalt applied to the subgrade. For light-duty parking lots with an aggregate base, a 3-inch layer of hot mix asphalt is suggested over a 6-inch aggregate base.