DG on a path – just plain DG or with added stabilizer?

[Naomi Sachs, ASLA, EDAC]

I got this email today from someone who is wondering about the best material for a small pathway at a school garden. Don’t have much experience with DG myself – anyone else care to weigh in? Thanks!

“I spearheaded an installation of an educational garden at a local elementary school last year. (It has been a huge success and we are getting ready for fall as school starts up again.) It is a total volunteer effort with a bit of grant money. Very cool project to be working on.

We still have some money left in the grant and the principal asked me about putting down Decomposed Granite in the walkways to help cut down on dust, mud and weeds. I always thought that DG was just spread out (a few inches thick), tamped and watered and that was it. But one place the principal spoke to, said something about having to bring in a cement mixer and adding a stablizer to the DG. Is that how it is usually done? I have never done big walkways before…When I did my tiny side yard, I just spread DG, tamped and watered. It has been great for years. Am I missing something? Any advice would be appreciated. We are trying to be careful with the grant money and don’t want to be taken for a ride. How is it usually installed?”

[Keven Graham]

It depends on the material but for the most part the installations we have used it in and they have varied including high traffic commercial applications, we have pretty much done nothing except put it down. We have in some situations had to put a fabric under neath to stabalize the soil. Decomposed granite is a very good path material and is generally pretty reliable.

[Clayton Munson]

It can be done either way. I think a lot of it will be based on the amount of foot traffic that it will get. usually using a 1/4″ minus granite. It can be done by just rolling/tamping it. Or there are many different types of liquid stabilizers out there. Your granite suppliers usually carry some form of it, or paver suppliers will often stock it as well. Soil-Loc Soil Shield LS is a common one. Basically you put down a layer of granite then spray the stabilizer on it, then another layer of granite and another coat of spray and repeat until you reach your desired thickness. Usually 2-3 layers will suffice for a pathway. Done properly it will last for years even with wet weather.

If you have a LAM laying around flip through it and you will find 3-4 different brands of stabilizer.

[Bob Luther]

I agree with the above mentioned methods, the factors that I have seen that require stabilizer are in areas of freeze/thaw (it may help), in areas of high rain (minimizes some repair work), in areas where there is high traffic (especially bikes or golf carts), and if it is a handicap access (check local regulations). otherwise plain DG is normally sufficient.

[Baxter (Gene) Miller]

With traffic (little feet) and the clay content of the DG you will have problems with all three of your concerns. We have spec’ed a little cement to be added to the DG as a binder. It lasts longer than the polymer based material. The City of Santa Maria, California has been using DG walks in all of there public parks with great success.

[Naomi Sachs, ASLA, EDAC]

Great stuff, thanks very much. What a great resource, this Land8Lounge. I think that for their purposes, plain DG will be just fine.

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