Before we get into how to prevent and repair potholes in gravel driveways and parking lots, it’s important to understand that there are two kinds of gravel driveway construction. Knowing how your gravel driveway or parking lot has been built is imperative when developing best practices for gravel driveway maintenance and repairing winter damage and potholes.
The first kind of gravel driveway repair is technically the correct way to build but is rare due to the cost. This method of construction is to first excavate twelve to fourteen inches below the final grade and build two different layers of gavel or aggregate in order to create a driveway base. The first layer is typically built from eight to ten inches of a fine stone blend, usually with the stones less than a quarter inch in diameter and approximately twenty percent being fines. This combination allows the contractor to layer in the base two inches at a time, water it, roll it, and let it dry before applying the next two inches. Once the entire base of eight to ten inches has been built, the driveway has a solid and nearly impenetrable base. Now the top three to four inches is made from a larger stone, usually 1/2”in diameter without many fines.
The purpose of this gravel driveway construction is to minimize driveway erosion and potholes created by the contraction and expansion of the ground. In theory, with a gravel driveway or parking lot created with this method, there is a lot less maintenance.
The second kind of gravel driveway construction is the most common, least expensive and yet requires the most maintenance. This method is to simply scrape away the top 3-4 inches of earth to create the foundation for the gravel driveway or parking lot and then spread 3-4 inches of a “road gravel” found at most local quarries. Although this is the simplest and most cost-effective way to build a gravel road or parking lot, it can become a breeding ground for deep and destructive potholes. As the earth expands and contracts with the temperature and gets soaking wet from significant seasonal rain, potholes seem to multiply like rabbits!
Now that you know there are two kinds of construction and you have identified which one you have, lets figure out the best practices for gravel driveway maintenance and how to repair those irritating potholes.
The most common way of repairing a gravel driveway pothole NEVER really works! It looks good for a moment but doesn’t last more than a few days and we all know that looks can be deceiving. This method is to simply loosen just enough of the gravel around the pothole that you can take that loose gravel and fill in the pothole. Usually, after doing this, most people will run their tractor or ATV tires over it to pack it down. While this looks like an effective way to repair the pothole, it’s really not repaired at all! That pothole (if humanized) is laughing at you and just waiting for the first rain to come or the first vehicle to pass through. Because that pothole knows that it was never really eliminated…it was just beautified! The first few vehicles to pass through will simply push the new gravel back out of the pothole and within a few days, it will look as though no work was ever done.
So, what is the proper way of maintaining a gravel driveway or parking lot and getting rid of those potholes? You have to get to the bottom of the problem and that means getting to the bottom of the pothole. No pothole will ever truly be fixed if you don’t loosen the gravel all the way to the bottom of the pothole and at least two feet around the pothole. The pothole shell has to be destroyed and the gravel surrounding the pothole regraded and packed back down before you have any chance of the pothole never coming back.
Remember the two kinds of gravel driveway or parking lot construction? If you have the first type, the potholes will not be any deeper than the base layer of driveway or parking lot. This makes them much easier to properly repair. With the first kind of construction, it is IMPERATIVE that you do not loosen deeper than the top layer of gravel. If you dig into the base layer, you have basically destroyed the integrity of the base and to properly repair it, means peeling off the top layer and loosening and regrading and resetting the base. This is a costly and time-consuming mistake. However, if you don’t get to the bottom of the potholes, they won’t be fixed; so, you get less potholes with this construction and it takes less effort to repair them, it’s a tricky balance that takes the right skill level and equipment.
If you have the second kind of gravel driveway or parking lot construction, you will get more potholes more often, have to work harder to repair them, but you don’t have to be quite as careful in the process. Essentially all you really have to do is loosen these potholes to the bottom of the shell, regrade and repack them. The secret to both types of pothole repair is to get to the bottom of the problem!
Besides knowing the type of construction used to build your gravel driveway or parking lot, what attachment for your tractor, ATV or mower should you use. Obviously, there are a lot of Tractor/ATV/Mower attachments on the market. Some of them are generic designs like box scrapers, rear blades and tine rakes but there are several Tractor, ATV and Mower attachments made specifically for grave driveway maintenance. When choosing your attachment to use or buy there are three key elements that attachments must have:
Gravel driveways and parking lots get compacted and hard to loosen. So, the attachment you use must have significant and rigid mounted loosening teeth or rippers. These loosening rippers must be able to loosen 3-5” or you will never get to the bottom of the pothole. A few attachments design only have ¼” loosening teeth and the manufactures requires the gravel to be soaked and states that it will take 20-25 passes to get the work done…give me a break! Who has that much time? Make sure you have an attachment that will quickly and effectively get to the bottom of the pothole.
A properly graded gravel driveway is critical in preventing potholes from forming. There are many ways to grade a gravel driveway or parking lot, but the main goal is to allow rainwater to shed to a low area away from the driveway. So, when maintaining a gravel driveway, keeping the original grade is very important. In order to do that, you must use an attachment that has leveling and grading capabilities. Many attachments can move material, but you have to be a skilled operator not to get a wash boarding effect on your driveway. Ideally, you will have or can purchase an attachment that has a “floating” or self-leveling grading blade as part of its design….yes, they do exist!
The final component of a properly designed gravel driveway maintenance attachment is the finishing component. Because, in order to get rid of the pothole, the gravel had to be loosened and then regraded, it is best if you compact or firm up the area where the pothole use to exist. So, a finish rake, seal plate or roller type finishing component to the attachment is a must.
