How to Apply Decomposed Granite

Decomposed granite makes an excellent informal pathway.

Decomposed granite is an inexpensive medium for walkways, small patios and flagstone patio fill. The fact that decomposed granite is water permeable yet does not wash away as easily as sand or soil makes it desirable for ecological designs. Decomposed granite areas still benefit from edging such as polymer edging, steel edge, or landscaping timbers to slow or prevent erosion.

Things You'll Need

• Measuring tape
• Landscape paint or with stakes with string
• Trencher or shovel
• Rake or hoe
• Landscape fabric or weed cloth
• Edging (if necessary)
• Decomposed granite
• Compactor

Instructions

1. Measure the total area of the space you will convert to a decomposed granite path or patio. Multiply this area by 5 inches to get the volume of decomposed granite you will need. Even though the finished granite area will only be 4 inches deep, you must get extra granite to allow for settling and compaction, as well as slight mounding to encourage water to drain from the center of the patio or walkway.

2. Mark the area off with landscape paint or with stakes driven into the ground on the edges and connected with string. Clear away all plant and organic matter in the area and deposit it in the compost pile.

3. Dig down 4 inches in the soil throughout the area with a trencher or with a shovel, starting at the edges and working your way to the center. Even out the bottom of the area with a rake and/or hoe. The usefulness of either will depend on your soil composition.

4. Lay landscape fabric or weed cloth over then entire area and a couple of inches up the edges. Weigh down with bricks or stones as you go to keep it from blowing away.

5. Install edging at this point, if necessary. Edging choices include polymer edging, steel edging (not recommend for childen's play areas), bricks or pavers, stones or landscape timbers. If the edging will not sit a half inch to a full inch over the top of the surrounding soil, install decomposed granite underneath the edging to get it to the correct height.

6. Install 2 inches of decomposed granite. For very small areas, simply walking over the area and using your feet to compact the granite will suffice. For most areas, you will need to rent and use a compactor. Run the compactor slowly over the entire area two or more times.

7. Add the remaining decomposed granite. Compact from the edges toward the center, allowing any excess decomposed granite to mound up from the edges toward the center. Make two or more passes over the entire area.

Tips & Warnings

• If the area is covered with persistent weeds that spring back from root matter (such as Bermuda grass or Johnson grass), solarize the weeds after you dig away the 4 inches of soil with clear plastic weighed down with bricks.

• Do not install granite paths or patios under a gutter drain. The torrential water will wash out the granite every time it rains. Re-route the water from the gutter, or re-route your decomposed granite path.

References

• Texas AgriLife Research and Extension Service: Decomposed Granite

Resources

• Landscape Design Advice: Decomposed Granite As Paving Material
• University of California - Berkeley: Paving Materials