How to Install a Flagstone Patio with Irregular Stones

Learn how to design and build a large flagstone patio with irregularly shaped stones.

I’m not sure that anyone could have prepared me for the strength needed and exhaustion that resulted from moving flagstone for 12 hours over 3 consecutive days, but it was a lot of fun. And I have new tricep muscles.

If you’re not up for the heavy-duty DIY projects (classified specifically as projects that require you to carry products that weigh more than your car), this might be a good instance where you’ll want hire some willing DIY-loving friends or a professional, but we did it, so there’s no reason to believe you can’t give it a try too.

Our patio is nearing completion, and we’re excited to have it ready for cookouts and late-night campfires into the fall months.

All planning behind us, after we finished excavating a space in the backyard and tamping crusher run to prepare for flagstones, we realized that we’d also have to lay sand in between the crusher and the flagstone itself. I knew it had to be there all along, but I hadn’t ordered it when we had the other materials delivered, thinking I could save a few dollars and pull it from our local beach. After doing some research, we learned that the natural beach sand is commonly too fine and round-grained for landscaping applications, whereas the store-bought sands are more angular and rough and less likely to settle drastically. We learned our lesson by not doing this research upfront, because having a mere yard of sand delivered to our house this week ended up costing us another $100. And because the flagstone hadn’t yet been cleared into the backyard, the sand had to be dumped at the very end of our driveway, only extending the distance that we needed to carry it.

Luckily, sand spreads pretty easily and it only took us about an hour to get the sand moved bucket-by-bucket into the backyard. While Pete made the brunt of the trips, I controlled sand distribution using two 1″ PVC pipes and a simple scrap 2×4 board to screed the sand evenly over the crusher so that it was settled in a consistent 1″ depth over the whole circle.

We did this same exact process when we were laying the crusher itself, but I never actually showed in last week’s post how it was done.

If the sand is compact, it’s easy to create a firm, even base by dragging the 2×4 in different directions, as long as you keep the outer edges of the board resting evenly on the PVC pipes.

Once it was spread, we lightly tamped the area by hand, although in hindsight we’re not sure how much help that provided. It did help to anchor the surface a little bit, but as soon as we began carrying flagstones over it, it loosened back up underfoot.

Breaking into the palettes of flagstone was by far the most exciting stage of the patio-building process. We had bought two palettes (a whopping expense) after being advised that each palette of irregular rock was capable of covering anywhere between 60-80 sq. ft. of space. Our patio is roughly 160 sq. ft., and we knew that one palette wouldn’t cut it; frankly, we worried that two might not be enough either.

We started by pulling several of the pieces into the backyard. Communicating the real size and weight of these pieces is kind of hard in photographs, but consider that the big one in the lower right could stand vertically and be up to my hips; heavy stuff.

Moving the flagstones into the backyard was a challenge by itself. The backyard wasn’t accessible by the delivery vehicles, so we were left to transport the flagstones about 50 feet from the driveway into the patio area by hand (most often, Pete and I carried them together). For the really heavy and thick stones that were far too cumbersome for us to safely carry that distance, we relied on a borrowed dolly cart.

Hoping to use as many large pieces of flagstone as possible, we spent about three hours carrying, laying, and leveling the first of the flagstones into the patio. As I often comment, it takes a lot longer than you’d think, and this next picture goes to show exactly how far we got in those few hours.

On our second day of stone laying, we began to find that it was harder and harder to make the flagstone puzzle come together easily; as a rule, we tried to create patterns that wouldn’t leave us with obscure, narrow spaces, since our palettes didn’t contain many tall narrow stones to fill those gaps.

We continued to pull fresh stones from the palettes into the backyard so that we had a wide selection to browse and pull from. The backyard essentially became our own little quarry.

Getting each stone well-embedded and stable in the sand was the time consuming part, and Pete served a bigger role in the process, since he weighs more than I do and was able to stomp them into place effectively.

It wasn’t until Day 3 of our patio installation that we really found ourselves in a bind. Constricted by the shape and size of our flagstone inventory, we began needing to customize the size and shape of some stones to fill in spaces and finish the space.

The easiest way we found to do this was by marking on the stone where a break needed to be made (you can see a faint line made in the dust in this below picture), and then tapping away gently at the stone edge so that it could break away cleanly. In nearly every instance, we had no problem customizing the size of the stone without bringing heavy-duty saws into the equation.

Alternatively, you can just stand a stone upright and let it fall hard to the ground (landing on a brick or another rock) and allow it to self-fracture into assorted smaller pieces; we did this a few times when we just wanted a natural break or a bunch of slightly smaller pieces.

After three days of hard work, we were left with our pretty stone patio:

We can’t stop standing at different points in the yard and admiring it.

As of today, we’re prepared to begin filling the cracks with polymeric sand and another little something special. 

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