How to Expand a Rock Driveway

What You'll Need
Wooden stakes
Plate compactor
Landscaping fabric

Rock driveways are beautiful and can last decades without any major repairs. Rock driveways do, however, need regular maintenance. If you already have a rock driveway and are looking to expand it, you should be able to complete this job with no problems. Like many do-it-yourself projects, you will need to do some planning and have a lot of patience. For this particular job, you will need to acquire the rocks from a quarry or home improvement center. You will also need a plate compactor. You can rent this from your local home improvement store or a landscaping supply store.

Step 1—Dig out New Area

Before you begin, you should map out the plans for your new driveway. You can do this with ease on graph paper. The graph paper will even allow you to draw the driveway to scale. Once you have the new design mapped out, place wooden stakes at the corners and pull string from stake to stake. This will allow you to work with a guide and straight lines.

With the string guiding you, dig out the new area with a shovel. You want to dig down below the top soil. If you were creating a totally new rock driveway it would be wise to dig down at least 10 to 12 inches. However, because you are expanding a current driveway, you should try to match the dimensions. However, if the current driveway isn’t at least 4 inches deep, you should start over and build a completely new driveway.

Remove the soil from the work area. 

Step 2—Take Measurements

Now that you have removed the top soil from the new area, take measurements to determine how much rock you actually need for the expansion. Note the length, width, and depth of the new area. To calculate the number of yards of rock you will need for the job, multiply the width by the length by the depth. That number should then be divided by 27. Here is the formula: (width x length x depth)/27.

Step 3—Compact the Soil

With the new area clear, you should use a plate compactor to go over it. This should be done several times. The soil will need to look flat and tight. If you see any ridges or fluffy bumps, you need to continue with the compacting.

Step 4—Lay the Rock

Before you lay the rock, you need to put down a layer of landscaping fabric. This fabric will keep silt and organic debris from contaminating the layers of rock. Cut the fabric to size and lay it over the compacted soil.

The type of rock and manner in which you lay it is going to be determined by the current driveway. Ideally, you want to use sharp edged rock and gravel. This will allow the edges of the rock to interlock and not move when the pressure of your vehicle is applied.

Ideally, you want the first layer of rock to be large, fist-size gravel. The next layer should be about the size of ping pong balls and the final layer should be about the size of marbles. You should apply pressure from the plate compactor after each layer. 

Step 5—Compact the Rock

With all of the layers applied, add additional pressure with the plate compactor. You may want to apply pressure over the entire driveway to make sure it is even.

That’s it. You can expand your rock driveway in five easy steps.