Over the years even the best-built asphalt driveways will develop bumps and hollows. Some of those hollows will eventually become potholes that can make your driveway a distinct pain to drive on, unattractive to look at and very expensive to fix if you hire someone to do the job. Fortunately, you can fix those potholes with some sweat equity and a few dollars using tools you've already got an inexpensive patching material available at your home store.
What causes potholes?
Asphalt roadways and driveways are made in a similar fashion. The base is made from compacted earth and gravel (for drainage) then covered with asphalt (basically a mix of tar, oil byproducts and small aggregate gravel) that in theory keeps moisture away from the base. However, over time the heat of the summer sun and the weight of vehicles driving on the surface will cause small cracks to form in the surface and water will get down into the base layer. Once water is in the underlying ground it will freeze (and expand) in cold weather, displacing gravel and earth and creating a void under the asphalt surface. Eventually, that asphalt itself will cave in and presto, you've got a pothole. (Even in areas where the temperature doesn't get cold enough to freeze, the water will eventually displace base gravel and earth and create a pothole.)
What you need to fix a pothole:
Fixing your pothole
It's best to fix a pothole on a warm dry day. Remember, we did say sweat equity was required.
Use your shovel to dig out any loose asphalt or gravel in the hole itself. Be sure to get rid of loose but still slightly attached pieces of asphalt. You want to get right down to the compacted gravel base of your driveway.
After you've removed the loose pieces, use your broom or shop vac to clean up the hole. Make sure you get rid of all the loose gravel in the hole or your repair won't bond well.
Once your pothole has been cleaned up, give it a quick spray with your hose. You don't want to soak the hole, just make sure you wet it enough to keep any dust settled.
Fill newly cleaned up and dampened hole with asphalt cold patch to about 1/2 inch above the surface. Starting at the outside, tamp the patch down using the end of your 4" by 4". Tamping is hard work but it's important you compact the cold patch compound or it will quickly deteriorate and you'll be back doing the same job in a year or so.
If you have a tough time getting your hands around a piece of 4" by 4" you can buy hand tools specially designed for tamping or rent a power tamper at your home store. Although it doesn’t really do a great job of tamping around the edges of the hole, another alternative is to lay a piece of plywood over the repair and drive your car over it a few times.
Finally, throw some sand or sweep some dust over your patch so it will blend in with your driveway and the patch material won't stick to your shoes or tires.
Fixing a pothole is a hot, messy, dirty job. However, the upside is that you probably already have most of the tools you need in your garage if not, be sure to Build Your DIY Toolkit and the cold patch is readily available and cheap at less than $10 a bag. If you take the time to do it right you'll save yourself hundreds of dollars.
All in all, a pretty good payback for a little bit of sweat equity.