How Thick Should an Asphalt Driveway Be?
Base and asphalt depths from asphalt industry guidance, and what to ask for in a written bid.
The Colorado Asphalt Pavement Association says an ordinary residential asphalt driveway should have a 2-inch bottom course covered by a 1.5-inch surface course, over a base of 6 to 8 inches of crushed aggregate. For an overlay on an existing driveway, it says 1.5 to 2 inches of surface mix is usually sufficient.
The asphalt
The Colorado Asphalt Pavement Association's driveway brief, published by the Asphalt Institute, says that for best results the ordinary residential driveway should consist of a 2-inch bottom course covered with a 1.5-inch surface course, and that densely graded surfaces work well for driveways.
The base
The same brief says a base course of 6 to 8 inches of crushed aggregate is usually adequate, spread evenly to the proper thickness, line and grade, and compacted with suitable rollers and compactors.
Below the base
It says the subgrade should be graded smooth, made free of organic material, and have weak spots undercut and replaced with suitable material, and that the design should account for the subgrade soil type, drainage, utilities and the loads the driveway will carry.
Overlays
For an existing driveway, the brief says an overlay of 1.5 to 2 inches of surface mix is usually sufficient, after weak spots, holes and large cracks are cut out and patched, with a tack coat on old weathered surfaces.
Get it in writing
The National Asphalt Pavement Association says a professional bid should include the thickness of the pavement. The Colorado Asphalt Pavement Association says the contract should spell out material types and thicknesses. That is the simplest way to compare two estimates.
Keep reading
Frequently Asked Questions
The Colorado Asphalt Pavement Association says a 2-inch bottom course covered with a 1.5-inch surface course, over 6 to 8 inches of crushed aggregate base.
The Colorado Asphalt Pavement Association says 6 to 8 inches of crushed aggregate is usually adequate.
The Colorado Asphalt Pavement Association says an overlay of 1.5 to 2 inches of surface mix is usually sufficient.
Yes. The National Asphalt Pavement Association says a professional bid should include the thickness of the pavement.
Sources
The figures on this page come from these sources, read on 2026-09-25. None of them is South State Paving's own claim.
- Colorado Asphalt Pavement Association (published by the Asphalt Institute), Best Practices for the Use of Asphalt Driveways, technical brief
- National Asphalt Pavement Association, Hiring an Asphalt Contractor for Driveways