An expensive but new product is out on the market that creates a hard surface for Decomposed Granite pathways and patios. This product, called TerraKoat, is sprayed on with the instructions below.
One note: There are other liquid stabilizers out there that DO NOT work. This is because the solids content of these other products (like G3) is lower than the TerraKoat. What that really means is the company that makes the G3 waters it down. Another difference is that the TerraKoat contains a proprietary admixture that increases the longevity of the surface. Wheeler Zamaroni has compared both products in real life applications and they found that with TerraKoat you end up with a stronger more durable surface. Therefore, if you are NOT using TerreKoat, then use a powdered stabilizer. TerreKoat costs about $15 gallon. A gallon will do about 20 sq. ft.
Here are the instructions from their application sheet. You will notice that they recommend preparing the surface just as I do in detail in my eBook Decomposed Granite and Other Materials for Walkways
TerraKoat EX Industrial Strength Stabilizer
1. AGGREGATE SELECTION FOR FINAL SURFACE: Select an aggregate that contains a variety of sizes. For instance, crushed stone mixes such as 3/8 minus, 1/4 minus or 3/16 minus work well with TERRAKOAT STABILIZER, where as single size aggregates like 3/8 rock or pea gravel are not suitable. Screenings with extremely high fine content are not suitable either. To ensure compatibility of selected aggregate with TERRAKOAT STABILIZER, prepare a test area.
2. STRUCTURAL STONE BASE PREPARATION: Before starting the actual project, factors such as climate, native soil type, amount of use, should be taken into consideration. As a rule of thumb, “The better the base preparation, the better the results.”
For optimum performance, install 4 to 6 in. of 3/4 minus crushed stone, then compact using a vibratory plate compactor.In restricted areas where a compactor will not fit, use a hand tamper.
3. SURFACE AGGREGATE: Spread surface aggregate over the compacted structural stone base. Rake or screed to the desired level, and slope to allow water run off. Do not compact until after TERRAKOAT STABILIZER has been applied.
4. APPLY THE TERRAKOAT STABILIZER: Using a watering can or pump sprayer, apply the TERRAKOAT STABILIZER to the surface at the rate of 20 ft2 per gallon for residential pedestrian use, or 15 ft2 per gallon for commercial pedestrian use. Allow TERRAKOAT STABILIZER to fully penetrate through the material
5. COMPACTION: While surface is still damp but not saturated, compact the surface with a vibratory plate compactor; 2 or 3 passes are recommended. In restricted areas where a compactor will not fit, use a hand tamper. The better the compaction, the better the results.
6. Seal Coat: After compaction spray TERRAKOAT STABILIZER over the area at the rate of 60 sqft per gallon.
Additional instructions include repairing cracks or using this product on an existing surface that was ill-prepared. For the complete instructions and additional information on TerraKoat, see my updated eBook on Decomposed Granite. I have many readers who tell me their installer did not apply the DG correctly. Depending upon the circumstance, this stabilizer might be very useful.
Instructions for rebuilding AN EXISTING SURFACE
1. Scarify or rototill 1 inch of the surface, break up any clumps, making any necessary repairs, and add new surface aggregate as needed.
2. Apply TERRAKOAT STABILIZER at the rate of 15 ft2 per gallon; allow liquid to penetrate.
3. Compact using a vibratory plate compactor. In restricted areas where a compactor will not fit, use a hand tamper.
Instructions for maintaining AN EXISTING SURFACE:
1. Apply TERRAKOAT STABILIZER at the rate of 20 to 45 ft2 per gallon. Some judgement will be needed, as consideration for absorption and desired results should be taken into account.
2. Compact any loose areas.
As in my eBook, TERRAKOAT recommends 3-6″ compacted Base Rock with a vibration compactor and a 2″ surface of DG. If you are using the Strybing Arboretum method because of poor drainage etc., then only 3/4″ of DG is needed.
For complete instructions on how to install a Decomposed Granite patio or walkway, see my eBook