How to Fill Gaps in Flagstone Patio

Flagstone walkway with shrubs lining walkway

If you’re having trouble keeping up with the weeds in your flagstone patio, the solution is to fill in the gaps. Adding new material to fill in patio gaps won’t just make maintaining the patio easier, it will also make it more beautiful, level, and safe. You can do this project all by yourself. Here’s what you need to know to fill gaps in your flagstone patio. 

Filler Options for Flagstone Patio 

To start, you need to choose which filler you’ll use to fix the gaps in the patio. You have several options: 

  • Sand: Sand is the most common joint filler, but it is challenging to keep in place and needs to be refilled. 
  • Rocks: You can use small rocks to fill large gaps, and gravel or crushed rock can be used to fill smaller gaps. 
  • Mulch: Bark and lightweight chunks of mulch are a great option for in-between flagstone. Cocoa shell mulch is small and curls, for a unique look. 
  • Plants: You can grow plants, such as grass or moss, in between the flagstone. 
  • Polymeric stone dust: You don’t need to use compacting equipment to firm up this material. That saves considerable expense and time on the project. This is also the best option for patios, as it fills in all of the gaps. 

At Grand River Natural Stone, we recommend polymeric joint material for our customer’s patios, so that’s what we will instruct you about.

Close up of flagstone patio

How to Fill Gaps in Flagstone Patio with Polymeric Stone Dust 

We use Gator Dust Bond and Techniseal NOCO as our primary options for filling in gaps in flagstone patio when the gaps are between ¼ inch and 4 inches. Here is how you can install it:   

  • Pour: First, pour your stone dust everywhere you want to apply it. The flagstone should be completely dry before you start this process. Ensure it fills up all of the space that you want to fill. It won’t expand in the activating process. 
  • Level: Unlike with sand, leveling polymeric stone dust is crucial. Also, ensure that there is no dust on the stones themselves. 
  • Water: Next you need to water the stone dust. Start at the lowest point of the surface and set your nozzle to shower or a gentle spay. Thoroughly wet the dust without letting it wash out of the joints. 

Once the stone dust has dried, it is safe to be walked on. Be sure to follow the specific instructions from your stone dust manufacturer. 

A flagstone patio can go from an eyesore to a beautiful centerpiece for your yard when you use the correct materials and technique to fill in flagstone gaps. For the best material and more information on how to fill in flagstone gaps, contact us today.