Decomposed Granite or simply DG is an excellent decorative inorganic landscaping surface material. It can be used simply for ground cover areas, pathways and trails, filler for hardscape joints, and even driveway material. For the purpose of this article we are going to focus on the use of DG for ground cover applications. We have seen a recent explosion in the number of installations and search engine inquiries for decomposed granite. Many of the installations we see are wonderful and are holding up well after years of use. Unfortunately we are also seeing DG being used where it shouldn’t be and results in a failed installation where no one is happy with the outcome. Decorative Stone Solutions feels now is the time to let everyone know that DG is not the perfect product for every application and there are some basic truths regarding the Do’s and Don’ts of DG installs.
What Is Decomposed Granite?
First, it helps to know a little bit about decomposed granite and why it's such great material for landscaping. Decomposed granite is a natural rock product similar to small gravel; however, it contains more "fines" or rock dust. Decomposed Granite is the term used in landscape industry to describe a granular stone surfacing material (not always granitic in origin) which consists of particle size ranging from 3/8" maximum down to very fine rock dust particles. This mixture of sizes allows for the correct blend of large particles "strength, medium sizes "space filler", and fines "binders". You may hear one or more of the following terms depending on where you are located in the country, all of which are describing products which have the same behavioral characteristics as decomposed granite: Rock Dust, Crusher Fines, Disintegrated Granite, & Chat.
The best part about decomposed granite is that it's relatively inexpensive compared with other solutions such as concrete or pavers.
Cost typically start at $40 to $50 per cubic yard for locally available options, whereas more exotic colors will be higher.
Decomposed granite is also available in over 30 different colors as well as a number of different shades within each color. All D.G. colors are the natural color of the stone it originated from and no dyes or coloring agents have been added.
You'll be able to find a shade and color that suits your exterior the best. Designers also have the option of using multiple shades and colors in order to add depth and interest to their projects.
There is even the option to have two or more colors blended, such as green and white, in order to create unique and dynamic colors
When being used for landscape ground cover applications, typically we like to see decomposed granite installed at a 3” depth. This can be as simple as evenly spreading the loose product over the prepared area with either man or machine power. We do suggest at least a manual hand tamping of the material once spread to keep it from migrating about or behaving a little like sand where it can leave footprints when walked on. It can also be frustrating to keep it from tracking into surrounding areas if it is left too loose (think sandy feet from the beach when getting in the car). A weed barrier underneath is not a bad idea, but isn’t right for everyone. See our previous article on this topic here.
The material can be left semi-loose as described above or if a more stable surface is desired, it can be wet and machine compacted forming a much harder and more stable surface. There are even soil stabilizers that can be pre blended or added after installation for heavy use pedestrian and vehicular traffic areas. Here are some of our stabilized DG options DSS- DG - Product Finder
The pro’s and cons of loose vs compacted are:
After reviewing the limitations of using DG as a groundcover, the #1 takeaway should be:
Do not install on a slope that is greater than 2-4% or that has water channeled to run over the surface
It doesn’t matter if it is compacted or not, when there is enough water running on it during a heavy rainfall or irrigation break, there will be substantial erosion. Sometimes when the slope is not very steep the damage is minimal and can be easily patched or repaired after each storm as part of routine maintenance. But most often we see washouts that resemble a mini North Dakota Badlands landscape. Whatever or whoever is downhill from the install will not be pleased.
Decomposed Granite is ideal for creating interesting color and visual appeal in a xeriscape type landscape. It is no coincidence that these landscapes are most prevalent in dryer climates where the chance for erosion causing rain events are least likely. So if your project is on sloped ground in a wet area be warned!!!
Landscaping With Decomposed Granite
Non Stabilized DG is an attractive and incredibly versatile product which can be installed successfully in a wide variety of landscape ground applications. However, its use should be limited to fairly flat or very gently sloping areas to avoid the erosion issue mentioned above and seen below.
Take a look at the wide variety of our decomposed granite offerings so you can incorporate one into your next project today!
Be sure to select the location the project is located as well as the appropriate category filter. DSS- DG - Product Finder