We recently redid the gravel between a flagstone patio at a home this week and it prompted the question as to the best material to put between flagstone. Whether you are just starting out with a brand new patio or redoing an old, tired one, filling in the gaps between the flagstones is a necessary task to ensure the flagstone stays put and doesn’t promote weed growth.
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Yesterday we worked with a client that had a 5/8 inch gravel between all of the flagstones that were originally installed about two years ago. The problem is that there was enough space between the gravel to allow dirt, seeds, and weeds to grow. Also, with enough space between these rocks, the flagstones shifted, allowed for rocks getting underneath the flagstone and lifting up in certain places, and cause the entire patio to be uneven.
We pulled out as much of the gravel as possible and instead added a 1/4 inch minimum crushed gravel. This added a cleaner look to the patio and once it is pounded in properly and the rain hits it, it creates a type of cement. Although it’s not permanent and can be pulled up, it will fill in the gaps, expand, and not sneak under the flagstone. This also prevents a lot of weeds, seed, and dirt from creating spots for weeds to grow.
This type of crushed gravel will last much longer than a more coarser shape. It also adds a more seamless look to the patio. This could almost look like a stamped patio or permanently cemented in Flagstone, even though it’s not permanent. Given a little bit of time with settling, the weather, and rain, and this will create a more permanent look solidifying the stones in place and making it much easier to sweep off, brush, and prevent weeds from growing.
Polymeric
Polymeric sand or poly-sand is a unique mixture of fine sand combined with other additives, typically polymers, when bound with water will form a surprisingly strong glue. This will lock the sand particles together helping secure pavers in a uniform and durable surface. When installed properly, the hardened sand will lock pavers in place and create a more effective weed and insect deterrent but will still allow water to drain freely. The last thing you want is a lake on top of your patio.
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However, just because polymeric sand is common, doesn’t mean it’s always the best material for the job. It can be easy to install and it stays in place but over time, it can crack or stay solid on top and leave avoid underneath.
Sand
Sand is often a traditional material used between the cracks of pavers depending on if it’s irregular pavers or square ones and how close the gaps can be. The small granules will fill in the gaps between stones without leaving spaces. Once completed, you can brush the sand into the sandstone gaps with a push broom. The smaller sand works better for flagstones that are closer together. The patio we worked with yesterday had gaps anywhere from 1 inch to 6 inches between the stone, so a 1/4 inch gravel really was the best option.
This is why I always recommend going with crushed gravel again, it depends on the type of patio and the gaps we have to work with. Every patio, paver, and the foundation is different so I like to assess the situation before locking down the type of material were going to use.
Give me a call and let’s discuss your options, whether you’re creating a patio or rebuilding one, and what works the best for your lifestyle and your budget.
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Please give me advice of what’s best to fill in the small places between flagstone pavers. We now have a type of sand, dust filler which needs replacement due to wearing away and weed growth. My husband wants to use concrete. I read a polymer sand is best. Please advise. Should we use concrete?
Either refill voids with 1/4″ crushed granite or polymer sand. Polymer sand will harden in the presence of water but may leave a hazy film on the stone. Concrete is not advised.
I am in the final stages of putting in DG between is that the wrong material for flagstone
I have a flagstone walkway. It has gaps that are bigger than other. I have put in 3/4 inch for base and pea gravel for topping. Also used screenings to try to solidify the pea gravel but gravel is still coming up and loosening
I have an existing flagstone patio which had sanded seams that that are floated away by rain and allow weeds. I want to convert the seems to dicondra which does well here so I purchased two rolls of perforated dripline one with 6” and one w/12” spacing to be connected to my existing 1/4” drip line in several places , dig out the seems a little, lay and staple the line down and top with soil and seed. Will this work?
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I have a flagstone patio that was dry laid on top of a concrete pad. I used the polymer sand but it mildewed. That is when I found the concrete underneath the patio. I currently have pea gravel between the joints but it continually comes out of the joints when I blow off the patio. What should I try next? I would like to be able to blow the leaves and debri off the patio.
My flagstone around my ponds We are full of weeds and grass. I am pulling all that out and putting in silica sand. What do I use to set it? I would like to not do it again and again.
We moved into a home with a flagstone patio that has pea gravel in between them, however it’s very messy and can’t sweep it or leaf blow without gravel going everywhere. I like the look of the pea gravel. Can you recommend a permanent resin binder product to mix with the pea gravel to use in between the flagstones to continue the pea gravel look but will stay put?! There is a product called EkoFlo Permeable Pebble Binder. Are you familiar with this enough to recommend it? Or something else? Please help I’m exhausted. Thank you for reading this.
We recently just did a flagstone pathway. We used crushed rock for in between the flagstone. Our problem now is that the crushed rock will not stay in place. What can we put over the crushed rock to help it stay in place.
I have been doing research on this question myself, I am not 100% sure its effectiveness on crushed rock (so far pea gravel has been the most used but I imagine it would work on crushed stone too). A resin spray over the rocks should hold it in place. You have to be very careful though as to not get it onto the flag stone (you can like tape off the flagstone like you’re painting.
Hold the leaver blower higher up and move it in quick cirlces; gravel moves less distance but the light stuff goes a flyin’
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Very helpful article, thank you. When you say 1/4 inch minimum of crushed gravel is that referring to the size of the individual gravels, or the depth that you are installing between the pavers?
I had my landscaper reuse larger flagstone (was the pathway laid in dirt) to construct a small patio. The stones are laid in coarse sand. The gaps are large so polymeric sand didn’t work. Could I just cement the stone in place? It;s just me so Im considering taking up the stone in a smallish area, pouring a bucket of concrete then laying the stones back in place.
Thoughts?
What about flagstone that is inside of a flower bed with mulch? What would you recommend between those stones.. Don’t want weeds but willing to put moss or some kind of plant in as long as it won’t grow completely over the stones. mulch alone doesnt prevent the weeds live in PA