Hello there! Today, I will guide you through decomposed granite installation; from start to finish. Scroll on.
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Decomposed granite is a budget-friendly surfacing grave. It is composed of naturally broken-down granite rock that has weathered over time to a composition of rock chunks, medium-sized particles, and rock fines (dust).
- Rock chunks
- Medium-sized pebbles as filler material
- Fines (clay and silt) as the binding material
The resulting gravel compacts quite well to form durable surfaces such as beautiful pathways or driveways. The more “fines” in the material, the more stable the surface can be.
But DG is best installed on flat surfaces with minimal runoff. It does not fare well on steep slopes as it is easily washed away. Also, avoid placing DG under downspouts or gutters or too close to your house where it can be tracked indoors.
Sometimes stabilizers or binding agents are pre-mixed into the material to improve durability and make the surface more resistant to erosion and weed growth. The supplier may mix the binder on-site or at the plant before hauling it. There are also spray-on stabilizers available at landscape supply stores and stone yards that work quite well.
In the following sections, we look at the installation process. This should be relatively simple with some basic DIY skills, access to water, and a drum roller, hand tamper, or vibrating plate compactor.
Gather Tools & Materials
You want to have some decomposed granite, a compactor, a beam and line level, edging material, a watering hose, and any other paving material, like turf or precast concrete pavers.
Decomposed Granite:
You can buy Decomposed granite with or without a stabilizer mixed in. If you can’t get stabilized DG, don’t fret – get some soil stabilizer and follow the provided instructions.
Pick a color of DG that’ll match your landscape and the exterior of your home. Colors include desert gold and brown. But keep in mind that color depends on where the DG is mined.
You’ll want about 2 to 5 inches of DG, depending on the pavement. Multiply that by the surface area of the pavement and you get a rough estimate of the required volume. Get extra material (about 30% more) to account for compaction and to keep a stockpile around.
Edging materials
Next up is edging material. Edging creates a border around the DG and keeps it in place.
The edging should be about 2.5 inches off the ground. This way you can dump in the DG to about the same depth. You can use;
- Pressure-treated wood (redwood, cedar…)
- Steel edging
- Pavers
- Concrete
- Bender boards
Landscape Fabric (Heavy Duty)
Heavy-duty Landscape fabric is laid on the subgrade, below the base layer to prevent the gravel from sinking into the soil and to separate the soil from the gravel
Compactor
You can use a drum roller, a hand tamper, or a vibrating plate compactor to tamp down the DG into place to form a stable and durable surface.
Metal Rake
To spread the aggregate and even out the surface before compaction
Hose & Nozzle
This will dampen down the DG enough for compaction, but not too wet that it cakes up on the hand tamper, roller, or vibrating plate compactor.
Measuring tape and marking paint
To accurately measure and outline the paving area
Step-by-step installation
Some planning and prep work will be in order prior to installing decomposed granite.
Contact the utility service to mark any utility lines running through the area to be worked on to avoid trouble down the line. Also, check out the local building and HOA codes that may regulate the style and construction of any paved surface.
1) Layout
Planning is essential whether you are building a fancy patio, a walkway, a driving surface, or edging around flower beds or firepits.
Once you have settled the desired pavement, get out your measuring tape and mark the area where you want to lay down the DG.
Measure the elevation (slope) using a laser or beam level. This will be a guide on how to level your pavement or whether you will need steps or not.
2) Ground (Sub-grade) prep
Now, let’s get dirty!
- Clear out weeds and cut the sod in the designated area.
- Excavate or dig about 3 to 12 inches deep into the marked area. The depth depends on the intended use of the surface; 2 to 4 inches for walkways, and at least 6 inches for driveways and patios.
- Level the ground at the desired depth and backfill any low spots with soil. A vibrating plate or hand tamper will make it nice and firm.
- Lay landscape fabric and anchor it using ground stakes.
3) Add a Base layer (sub-base)
You need a solid base for laying the DG. This is by means of laying a base material such as crushed aggregate on the subgrade (soil).
You can use a class 2 road base, going for a depth of 2 to 4 inches, depending on the traffic you expect. For heavy traffic areas, use a thicker base layer with larger stones to withstand the load. Level the base layer, get it nice and damp, and then compact it real well, aiming for at least 90% compaction.
Also, consider the type of soil (subgrade). If your soil is wet, the gravel base should be deep enough to minimize settling. For heavy freeze and thaw cycles, the gravel base should be deep enough to reduce heaving. In arid areas, you can skip the gravel base altogether and add the DG right on the subgrade.
4) Install Edging Material
The edging keeps the Decomposed granite in place, preventing it from shifting. It also marks the boundary between the paved surface and the surrounding bed or lawn.
You could use metal edging, natural stone barriers, bricks, precast pavers, pressure-treated wood, bender boards, or other composite materials. The top of the edging should line up with the top surface of the DG.
Anchor and hold the edging in place using ground stakes driven deep into the ground.
5) Spread the Decomposed Granite
Now, if you are going for 3 inches of depth or more, lay the DG in 1.5-inch lifts, and screed the surface with a 2 by 4 plank or metal screed to level it out.
Add each layer, spread it using a rake, moisten it, and then compact it to interlock and solidify the surface. Be sure the water soaks all the way down to the bottom layer.
For larger areas, rent a vibrator plate or drum roller, but for smaller areas and around the edges and corners, a hand tamper will do.
Now, for heavy traffic areas, consider using stabilized or resin-bound DG. The stabilizer is usually pre-mixed with the DG before installation to bind the particles together but still allow for some infiltration. In addition, for an ADA-compliant surface, you need a stabilizer.
Over time, loose aggregate will chip off the surface. Water it down and recompact it.
What next?
Once installed, DG Maintenance is pretty straightforward. Weeding and replenishing any low spots impacted by foot traffic, erosion, or vehicles is all you need to do.
This process might take some time and effort, but in the end, you should have a surface that’s mighty darn appealing.
So there you have it. Hope to see you soon!
