How To Fill Gaps in Flagstone Patios

Installing a flagstone patio is not an easy task. It takes time, effort, and precision to make sure it is perfect. However, there are times when the unthinkable happens.

You realize there are gaps between the stones in your flagstone patio. Read on to find out how to fill gaps in flagstone patios.

Flagstone patios are a popular and luxurious addition to any home. The problem is, once the patio and walkways are installed, they can be plagued with any number of nagging problems.

The most common of these problems is gaps in the flagstone. These gaps can be caused by many different things, like soil composition or uneven surfaces.

Luckily, you can fix these gaps easily with some creative ideas. Covering gaps with mulch or different types of rocks can hide them and provide some natural appeal.

When the gap is more significant, you’ll need more than just rocks. Here are some ways to fill gaps in flagstone patios that anyone can do!

Things to Consider Before Filling those Gaps

How To Fill Gaps in Flagstone Patios

It can be a challenge to cover gaps or seams in flagstone paving. There are a few different ways to fill the gaps, depending on your needs and budget.

Whether you need a temporary fix or a more permanent solution, here are A few things to consider before you start filling those cracks!

  • How will the flagstone area be used – This is an important question. If the flagstone patio or walkway will be used for foot traffic, you’ll want to make sure that whatever material you use won’t cause discomfort.
  • How has your patio flagstone been bedded-  No one wants to be walking on a patio that could fall out from underneath them. However, if your flagstone patio has been bedded properly (often, this is the problem), repairs like filling in cracks and gaps should last for many years or even decades.
  • What kind of budget do you have – Are you looking for a cheap fix, or do you want something that will last? Your budget will determine what type of material you’re able to use.
  • How big are the gaps – If the gaps are very large or too close together to make a solid surface, you’re going to want to use professional help. In this case, ask a contractor about your options before you decide how to fill in those cracks.
  • Will the flagstone patio be flooded – If you know that your patio will likely get flooded from time to time or if it does flood frequently, then you’ll probably want to avoid using just dry-laid materials like rocks and wood chips.

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How To Fill Gaps In Flagstone Patios

ways to fix the problem of flagstone gaps and cracks in and around your home.

There are several ways to fix the problem of flagstone gaps and cracks in and around your home. Here we’ll cover four basic ideas to fill gaps in flagstone patios:

Read: How to level flagstone

1) Growing Some Filler options on the Gaps

 If you have a lot of gaps or think it looks nice to have some growing filler, then there are many options for this.

You can plant grass or wildflowers in the cracks and allow them to grow.  The downside to this is you’ll want someone to water them regularly and care for them.

Another option is filling the gaps with any plant with small flowers or what looks like a ground cover.

Shrubs like lavender, thyme, and rosemary can grow between flagstones without obstructing too much of the view.

Once they start flourishing, you’ll forget about those gaps entirely! It may take a while for grass and flowers to fill the spaces, so it is recommended that you choose hardy plants and will survive different climates.

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2) Rock It Up!

Rocks are the simplest, most cost-effective way to fill in gaps. You can use sand or soil first to level out the surface between the cracks and then just put down your rocks before you bed them.

If you’re looking for something small and uniform, try using river rock or pebbles.

Large flagstone pieces also make great filler! Also, consider color when filling space with rocks – matching color schemes will create a more cohesive look.

3)Covering Flagstone Patio with Mulch/Wood Chips

Mulch is another simple way to fill in spaces between flagstones. There are mulches made specifically to fill gaps, so your deck space will look clean and cohesive.

Alternatively, you can fill the gaps with wood chips or other organic materials like leaves or straw!

This method covers large gaps easily and is also very affordable.

You’ll need to ensure that your flagstone patio does not flood often because this could be bad for the wood chips if they get saturated over time.

For best results, look for hardwood shavings instead of tree bark mulch. They will last longer and still give good drainage properties.

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ideas to fill gaps in flagstone patios:

4) Fill the Gaps with Sand

If you want to add a bit of color, then filling your gaps with sand might be the way to go.

You can even mix acrylic and washable paint into the sand first to create a custom color for your flagstone patio.  It looks particularly nice if you’re going for a beach theme.

Just remember to seal the sand well after you fill your gaps so that moisture doesn’t get trapped beneath them and eventually ruin your flagstone patio.

You can also buy special colored sands from craft stores for this purpose, but they may be hard to clean up afterwards!

Can you lay flagstone on dirt?

Flagstone is not recommended for installation on dirt because it is porous and will drain too much. It needs to be installed over a hard surface like cement.

Why do flagstones crack?

First, you want to check that the individual stones aren’t cracked or loose, as this can cause them to shift slightly over time.

If they are all good, then the problem could be improper placement of mortar between stones.

Can you use marble as flagstone?

Yes! Marble makes an incredibly beautiful patio surface stone. However, it isn’t very durable in its raw form, so you need to seal it or have a professional lay the flagstones for you.

Flagstone is an awesome material for many landscaping projects so long as you keep it level and properly constructed.

Use these tips above on how to fill gaps in flagstone patios if you have gaps or cracks appearing in your patio stone flooring!


  • Ricky

    Hi, I’m Ricky. I’ve been involved in lawn care and landscaping from when I was 15. To be honest, I didn’t like the idea of pushing mowers, collecting grass clippings, and maintaining flowerbeds at the time. But having seem the passion my parents had for gardening and outdoors and the effort they put in maintaining the health and beauty of our landscape, I couldn’t help but not only admire their hard work but also I became a part of it. As someone who loves to spend time with nature’s best, I find myself learning a lot more about gardening and outdoors on a daily basis. Not to mention I love to share the knowledge I’ve gathered over the years with my readers at We Mow Dallas. To be clear, I don’t have a Master’s degree in gardening or anything like that. Everything I’ve learned about gardening, landscaping, and lawn care spring from passion and engagement with my parents. And with a ton of free information out there, plus the ability to run tests and determine what works best for lawn care and landscaping, every day is an opportunity to learn and implement something new. My goal with We Mow Dallas is to teach you exactly how to maintain your lawn and landscape. And since I walk the talk in reality, you shouldn’t hesitate to join me in this wonderful world of landscaping and lawn care. K Beatrice

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