Sand in Joints

We have flagstone laid on decomposed granite, and the granite washes away too easily, so the joints are now deep ruts after three years. We had to have joints that let water through for our large sycamore tree. We'd like to fill them with sand --- any tips? I experimented with a bag of sand in a small area and it looks nice, but I'm wondering if the sand will eventually harden this way, as it doesn't seem to be hardening though I lightly water it every day. It remains loose. Am I too impatient?

Is there a specific sand that can be used? We experimented with a bag of "play sand" from the nursery.

Thanks for any feedback!

Comments for Sand in Joints

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Polymeric Sand drainage NEW
by: Alice

I used polymeric sand between pavers and love the end result. Now I want to install flagstone in another area and was thinking of filling joints with decmposed granite because I want the drainage. If I use polymeric sand and it hardens, does the water still drain through the hardened sandy?

Nice tip Richard
by: David

I'll have to add some of your suggestions to the site.

Thanks again!!

flagstone joints
by: Richard

Decomposed granite is a good choice for joints. We use a stabalizer with our decomposed granite that hardens the granite. Sand will wash away sooner than the granite...There is another product called polymeric sand that can be mixed then swept in the joints then lightly mist and it will harden too. Polymeric sand comes in two colors. Gray and beige..Certain polymeric sand are used according to the width of your joints.

They make polymeric sand, gator dust,gator sand, depending on your joint widths. All of these are good products except pricey...One fifty pound bag covers anywhere from 20 to 45 sq.ft. depending on the joint width and the flagstone thickness..


Polymeric Sand
by: David

You should try polymeric sand. It's a product that has come out in the last five years and we've heard it can fix problems like yours.

My dad has never used it, but we've heard good things about it.

Great luck with your project!


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