Justin White, Landscaping Lessons │ Breaking down decomposed granite – Santa Cruz Sentinel
As the trends in landscaping continue to evolve and evolve, you’ve probably heard of decomposed granite. Commonly called DG in its abbreviated form, it has become very popular in modern landscaping. Not only because of its aesthetic appeal, but also because of its functionality and economy. You may have considered using decomposed granite in your landscape, but what exactly is this hardscape material?
Starting from solid granite stone, the rock breaks down into finer particles after rain, wind and temperature conditions continue to weather it. For landscaping, the pieces of gravel are usually three-eighths of an inch or smaller. The gravel is then compacted into a semi-hard but permeable surface. DG is an excellent option for paths, driveways, patios, and even large areas of commercial facilities such as playgrounds and paths. As an organic material, its natural appearance appeals to many types of customers and can also help contribute LEED points for certifications in the construction industry. One of the downsides to DG is that it can erode over time or become soft after a rain event and potentially get into your home on the soles of shoes. Fortunately, there are plenty of binding options that can help you secure your DG in place while protecting it from the elements.
Crushed granite is available in a variety of shades including red, black, gold, and gray. It also differs in three main types of installation methods. We’re fortunate to have both a gray DG from the Aromas Granite Construction Quarry and a gold-colored DG from the Felton Granite Rock Quarry here on the Central Coast. Natural or loose DG can be used as a wood mulch replacement for distribution in trees and garden areas. It is also great for use in a bioretention tank where wood mulch wood is washed away by seasonal flooding. Since loose DG does not contain stabilizers, it is best to place in low-traffic areas where it cannot be tracked indoors. Stabilized DG is a mixture of gravel with a light binder that helps the material hold its shape more than its natural state. Most patios and paths are equipped with a stabilized granite because it lasts longer, is more resistant to erosion and its grainy texture offers traction for safe foot movement. Resin-coated DG creates a hardened surface that is good for driveways because the granite stays in place and creates an asphalt-like exterior. While it’s the most durable granite, it’s also the least permeable and doesn’t allow proper drainage.
Throughout my career, I have asked a variety of questions about the different types of GD stabilization and which are the most effective. The best option is to mix a binder with the product before installing the DG. The longest lasting and highest quality product on the market today is called GraniteCrete. This patented binder, together with water and DG, forms a concrete-like surface that is also permeable. It can be used in almost any application, and while it is more expensive due to the labor-intensive mixing process, the end result will last for decades. The next step is a spray stabilizer that is applied to the DG before compaction. Install the granite in your hardscape area, spray the stabilizer on as directed, then compact it for a finished patio, walkway, or play area. The sprayed-on stabilizer can lose its hold after a few years of rain or be washed away because it is not mixed in like the GraniteCrete. However, this is cheaper and less labor intensive. Finally, a stabilized DG can be achieved by simply mixing in portland cement, mortar, or some other type of concrete material. While this is not recommended for commercial use, the average homeowner with a few bags of concrete lying around can potentially stabilize their DG without much additional expense. You can create the mixture on concrete in a wheelbarrow at a speed of 15: 1 DG, then spread, soak and compact the material. Note that the concrete you are using may change the color of the DG. However, depending on the application, this can be a quick and easy way to stabilize your DG.
Decomposed granite itself may be a simple landscape feature, but applying anything other than loose DG is not quite that straightforward. Professional help is highly recommended as proper equipment and preparation are the basis for a successful installation. Some of the additional steps of the installation may include edging, sorting, and laying bedrock or root barriers. Don’t forget to use a compressor. To ensure the material stays in place, the gravel needs to be pressed firmly into the ground, and this is difficult, if not almost impossible, to do without a granite compactor.
Hope you don’t take this naturally occurring local granite for granted but find a way to incorporate it into your garden or project site. If you have large redwood trees lifting your concrete walkways, replacing those with decomposed granite can make troubleshooting and eliminating pitfalls a lot easier. Another helpful idea is in your trash can storage area of your driveway. These areas are usually weed and difficult to keep clean, but not when replaced with a low maintenance DG plaster. As small or large as your project may be, make your landscaping stone out of decomposed granite!
Justin White is the CEO of K&D Landscaping, headquartered in Watsonville, California, and was named “Business of the Year 2020” by the Pajaro Valley Chamber of Commerce. White is also the current president of the local chapter of the California Landscape Contractors Association (CLCA) on the central coast. He is involved in several nonprofits across the community and sits on the board of directors of the Santa Cruz Business Council. For more information on landscaping, outdoor and gardening requirements, contact K&D Landscaping at kndlandscaping.com.