When it comes to asphalt paving thickness, there are a few schools of thought. Some asphalt contractors will go with a thinner finished product to save cost and charge customers less for their work. That’s where the idea that 2 inches of asphalt is enough for a driveway came from. So, is 2 inches of asphalt enough for a driveway? In some cases, yes. However, we never recommend using only 2 inches because it doesn’t last long enough, temperature swings in Colorado are more likely to damage the asphalt, and in certain areas, swelling soils can break 2 inches of asphalt much easier.
For a residential asphalt driveway thickness, Colorado Pavement Solutions always recommends 4 inches of asphalt for a driveway. Four inches of asphalt is strong enough to withstand Colorado temperature swings and the weight of most personal vehicles. So, where did the notion of needing 9 inches of asphalt come from?
Different municipalities have different standards for municipal roadways. We believe that’s where this misconception came from. In certain parts of Aurora CO municipal roadways require between 9- and 11-inches asphalt. Most of Lakewood CO, on the other hand, requires 6 inches for their roadways. Six inches of asphalt is also our recommendation, and standard, for commercial parking lots.
Modern asphalt is a mix of petroleum byproducts, aggregates like stone and dust, and different chemical binders. For an optimal mix and surface of these components, you need a minimum thickness. The amounts of aggregate, layers and asphalt components depend on the region, road needs, and much more.
Can you ever do 2 inches for a driveway? Sure. There are situations when using 2 inches is advisable, if allowable by your asphalt company. Replacing two inches can save you time, energy, and money.
Mill / Overlay – If an asphalt company feels your binder course is in good shape, you can choose an overlay.
There are two options for renewing your surface layer, overlay, or mill and overlay. An overlay is only adding a new surface coat while mill and overlay involves milling up the previous surface layer before installing two inches of new asphalt.
You can choose an overlay only when the asphalt shows mild to moderate wear. If the asphalt is severely damaged, a mill and overlay will be required and is more expensive than an overlay only. Your asphalt contractor can help you determine the proper way to overlay your asphalt.
Two inches is the industry standard for asphalt overlays and surface courses because it properly bonds the surface course to the binder course. If a surface course is too thin it won’t have the surface area and other properties to properly bond which will result in raveling, cracking, and other asphalt issues.
There are many Do-It-Yourself projects that homeowners can tackle but replacing or installing new asphalt is not one we’d recommend undertaking. Pouring new asphalt requires expert calculations, proper planning, and flawless execution. Most homeowners don’t have the knowledge and equipment to install new asphalt, so turn to a professional.
Colorado Pavement Solutions will measure the correct amount of asphalt, choose the right materials for your tastes and budget, and put on a beautiful new blacktop. If you’re ready for some new asphalt, whether it’s a new installation or overlay, call or email us today.