I received a question today about the types of available decomposed granite (DG). This can be a bit confusing because there are a few different options for DG.
DG is essentially a combination of small granite pieces and granite fines. The fines in the DG make the material well suited for pathways and areas where it can be compacted. Typically we compact our DG installations with a vibrating plate compactor.
DG comes in two basic color ranges, brown and gold. The material is usually installed one of three ways.
1. Decomposed Granite with no additives: The DG is often installed on a compacted base of roadbase gravel and then compacted to make a pathway, seating area, or other application. The DG is typically hard packed but can move and has a sandy consistency (what comes to mind is a French Park with its long sandy alees)
2. DG with stabilizer agent: A stabilizer agent is mixed into the DG which prevents the material from moving around as much and gives it a more hard packed appearance. The material will still form a bit of a sandy layer on the top but it is much better than the untreated DG.
3. DG with Resin or “Poly Pavement”: The DG is mixed with a natural resin which creates a natural asphalt like material. This is the most expensive type of DG installation and we typically use it in high traffic areas, ramps and steps down hillsides, or driveway surfaces. It is frequently used in wineries for access paths and drives. The material will not run, and does not have a sandy consistency like the other types of DG.
While these additives make a great surface, the DG can become eroded if not protected from repeated water erosion. The most frequent culprit here is gutters or downspouts where constant dripping can erode the material.
DG is a great material where the design aesthetics are such where concrete would not work well or where a more rustic and natural look is desired. Both the untreated DG and the stabilizer will get somewhat muddy during rainy periods, so we recommend DG with resin for areas where access is heavy year round.
Below are some examples of the DG types:
Untreated DG Being Compacted
Decomposed Granite with Stabilizer Agent
Decomposed Granite with Resin Additive
Used for Ramp pathway