Weekend Project: My DIY Flagstone Patio

I imagine my recent flagstone patio project was a lot like the pain of childbirth.

During the process it was hell. But now that it’s done, doing another project like this doesn’t seem like such a bad idea.

My wife and I recently moved to the “burbs” outside of San Francisco so we could have a house with more space and a yard.

When we moved in, our new backyard was beautiful, but there wasn’t a ton of useable space. With the lush growth of plants, it felt a little claustrophobic.

Wouldn’t be nice, we thought, to turn part of our yard into more patio space?

But we didn’t want to mess with hiring people and paying a bunch of money. So we decided to do it ourselves.

Here is the story of how my wife and I made our own flagstone patio.

Step 1: Choosing the Style

When you create a patio, you have a few different choices:

• You could just pave it with cement
• You could use stones or brick, and then mortar them
• Or you could do what we did: lay down loose paver stones

First of all, we didn’t want to mess with cement. But even more importantly, we wanted good drainage since our backyard backs up to a hill that might get water runoff.

As for the pavers themselves, you can purchase prefabricated paver stones at home improvement places like Home Depot or Lowes—it’s easy and it can look great.

But of course, we chose to go the more difficult route.

Rather than using prefab stones, we chose flagstone, since it has a more natural look, it’s durable, and it has a wide variety of colors within it that mix well with the rest of your yard.

I have to admit, it was pretty exciting selecting the stone. Here’s a picture of our trip to the local stone supply yard, where we got to pick out our flagstone (2-1/2 tons to be exact).

With pavers, since you don’t use cement to fill in the gaps, you usually add sand, pebbles, or you can plant grasses or ground cover like moss in between. We chose bluish “river pebbles” as our filling.

Now that we had chosen the style, it was time to get to work.

Step 2: The Big Dig

With pavers, the general idea is that you need to lay down some gravel, then a layer of sand, then you place your paving stones, and then you fill in the gaps.

So you have to account for all of this depth when you dig down.

I saw a wide variety of suggestions online about how deep to dig. Anywhere from 3 inches to 9 inches.

Ultimately, we decided on about 5-6 inches. This would allow us to lay down about 2 inches of gravel, about an inch of sand, and then the paving stones, which were about 2 or 2-½  inches thick.

While the area was not huge, I knew that our soil had a lot of rocks in it, and was not easy to dig, so we ended up hiring two guys to do the initial dig. That way we could focus on the fun part—making the actual patio.

Ultimately, that was a good decision. 5-6 inches doesn’t sound like much, but digging down evenly over a larger area takes a lot of work, especially since our soil was pretty rocky. They ended up digging out about 6 cubic yards of dirt—and they hauled it away, which was a big help.

Step 3: Adding in Coarse Gravel

Now that the area was dug out, it was time for gravel. The gravel helps to create a firm, level base, but it also allows water to drain.

To source the gravel and sand (step 4), we went to another local place that sold landscaping rocks and other supplies.

At first we thought we would just transport the gravel and sand in our SUV. But after a few calculations, we realized that would be a bad idea because (A) it would be a lot of time and heavy-lifting to simply load and then unload the car, and (B) we would have to make at least 2 trips—maybe more—to get everything home.

Suddenly the $50 delivery fee seemed like a bargain.

Within a day, a big dump truck came to our house and dumped a pile of gravel and a pile of sand in our driveway.

The salesperson made sure to ask us which pile should go closer to the house. At the time, it didn’t seem important. But once I started hauling wheel barrels full of rock, I realized that even 10 feet can make a big difference.

We gradually added in the gravel and used a metal rake to spread it out evenly.

Once we covered the area evenly, we got out the tamper and started tamping it down. You want to avoid having your patio sink down or become uneven because you either didn’t add enough aggregate or you didn’t tamp it enough.

There’s really no trick here, except I tried to follow some advice that I read. Essentially: “if you’re not tired after tamping, you’re not doing it hard enough.”

Sure enough, it was a good workout. Here’s a picture of me looking EXTREMELY stylish in my “dad hat” and pulled-up socks.

After the first round of tamping, we looked at the area to see if any spots needed some additional gravel. Then we tamped some more. As they say, tamp big or go home.

Step 4: Layering and “Screeding” the Sand

Now that we had the gravel base down, it was time to layer in the sand. The sand fills in the gaps of the gravel to provide a stable base for the stones.

To ensure we evenly covered the space, we made little piles throughout the area before spreading it out. We “screeded” (a fancy word for “leveled” or “smoothed out”) the sand, alternating between using a 2” x 4” and a piece of cardboard. (you could also use a pipe or any other straight edge).

Some sources I read suggested doing another layer of sand after the initial screeding (I can’t stop using that word!). They also suggested being careful not to walk on the screeded (there I go again) area—like not walking on a mopped floor.

Once we got the gravel and the sand down, we optimistically thought it would only be another weekend or so for us to lay out the actual flagstone.

Laying the stone would be easiest and most rewarding part, right?

How wrong we were.

Step 5: Laying the Flagstone

Now it was time for the “heavy lifting”—literally.

Based on the square footage of our space, we purchased 2-1/2 TONS of flagstone. When I first saw those 2 big pallets delivered to my driveway, I was thinking “what did I get myself into?”

I thought we had ordered too much. But later I learned it was good that we got as much as we did, because of the irregularity of the stones. Having more selection made it slightly easier to find the right shapes to match with other stones. Also, not every piece was usable; I still have a half pallet of odds and ends that will probably become a stepping path one of these days.

Breaking Up the Flagstone

The guys at the stone supply place suggested trying to use the really large pieces around areas where you might put a table or where there might be concentrated activity.

Beyond that, we would need to try and split up the pieces into usable chunks.

Some sources I saw suggested that you could use a chisel; others suggested getting an electric tile saw.

We didn’t really want to do the tile saw, because (A) it seemed like a bigger undertaking, and (B) we were still embracing the whole “organic” look.

Then when we purchased the stone, the men helping us said we could just use a regular hammer and quickly whack the stone along a straight line. And after a few whacks, bam!

We were so excited. No need to rent a fancy tile saw. And it sounded like maybe we didn’t need even need the masonry chisel I had bought just in case.

Turns out it was a little harder than we thought. These were THICK pieces. Most of them were 2 inches. Some were close to 2-1/2 or 3 inches in some places.

So we tried various things:

….The simple hammer-along-a-line technique—no dice. There was no way a regular hammer could deliver enough power.

…Masonry chisel with hammer—still no.

…I even borrowed my father-in-law’s air chisel and air compressor to try scoring the stones before breaking them. That didn’t work either. They were just too thick and burly.

Ultimately we found that using a combination of a mall/sledgehammer and a blacksmith’s hammer (for smaller pieces) worked best.

To get the most precise cuts, you still had to whack repeatedly along a straight line. So apparently when the guys at the stone place said “regular hammer” they meant a massive mall.

What also worked for the really big pieces was to just let them fall off the pallet onto our driveway; often they would break into smaller, more usable chunks.

Then there was the problem of simply transporting them. These stones were very heavy—some of the bigger pieces would have been impossible for even two people to lift. So we used a flat dolly. We would tip one end of the stone up, wheel in the dolly and then slide it on. Without the dolly, I think I would have literally gotten a hernia.

Strategically Placing the Stone

Following the advice we got, we chose to lay out a few of the behemoth stones near the center. Then we chose one big stone that would be the base for my new gas barbecue.

After that, we focused on finding pieces that had at least one completely straight side. We used those to place against the edge of the walkway, since that was the only straight edge—and it would look really obvious and messy if the stone didn’t line up on that edge.

After laying out the front edge against the walkway, we started filling in one side of the yard. At first it was fairly simple, because we had a lot of stones to select from.

To make the patio as walkable as possible, we first tried to keep the gaps to around 1 inch. Later this became more difficult as the stone selection dwindled and we had to fit the remaining pieces into the puzzle.

At first we had some momentum. But as we progressed, it became the worst game of Tetris ever.

As soon as you found a stone that matched up with the existing pieces, you created a new edge that had to be matched by a new stone—on multiple sides. It was hell.

I kept thinking, if only we had chosen uniform paving stones. This would have been EASY.

This is what we wanted, I guess. The organic look…and we were paying for it.

Up until this point, this had been a combined effort with me and my wife. I was literally doing the “heavy lifting” of the stones, and she was helping pick them and decide where they went.

For the most part, it was going okay, except there was the occasional frustration and friction that comes with two people working on a big, pain-in-the ass project.

But once we were about half-way through, the stone placement started to get trickier. Tensions started to brim.

The Worst Puzzle Ever

This crazy Tetris game was hard enough. But to have 2 people look for stone pieces to fit ridiculous shapes was too much. We would have to look at the existing edge we were matching, then we’d have to go look at the stones we had, and then try to select the next stone—while also trying to anticipate what the new stone would mean for the rest of the puzzle.

Each time we would try a stone, I would need to lift it over to test it in place. And then if it didn’t work, I’d have to take it out of the way. Even using a measuring tape, it was a challenge.

So suddenly I had an idea:

“Babe, let me just take a crack at this.”

There really was no way to do this efficiently with 2 people. I knew that if I could get in a zone, and start to visualize the shapes, and keep in mind the available stones, I could go all Rainman on it and knock it out quickly.

It turned out to be a good decision for our marriage. After that, I was able to finish the remaining area in just about ¾ of a day. And my wife was able to go take care of some other things inside that she wanted to tend to. Both of us were happier.

Towards the end, as the stone selection dwindled, I had to make a lot more compromises. For the most part, the actual surface of the stones looked good. But there were a lot more jagged gaps in between. I tried my best to keep them as tight as possible, but more and more I was working with crazy triangular and other geometric shapes.

There was certainly no way I was going to go buy any more flagstone. And we couldn’t give up at this point. So I worked with what I had.

Step 6: Micro-Leveling The Stones

Now that all the flagstone was in place, it was time for some fine-tuning.

The initial layer of sand is meant to help stabilize the stones. But since many of the stones were uneven and different heights, we had to do some leveling and balancing to make things work.

We checked all the stones for height and wobbliness, as well as where each stone met.  We wanted to avoid edges or corners sticking up where someone might stub their toe.

Then we marked any of the stones that needed adjusting with green painter’s tape (as you can see from the pic, that was about half of them!)

Ironically enough, after all the delicate screeding (and warning to not walk on the already screeded sand), we ended up using our hands to place and smooth the sand. It definitely seemed to be more art than science.

My wife and I worked together on this; we would figure out the issue with each stone, I would tip up the stone, and hold it up while she added stone and smoothed it out by hand.

Step 7: Filling in the Gaps With River Pebbles

The final step was to pour river pebbles into the gaps. As I mentioned, some people use more sand in the gaps at this step or even plant ground cover. We chose river pebbles because of the look, and because we thought they would be more likely to stay put.

By this time, we physically and psychologically exhausted, and I was bummed that I felt like we had to make compromises at the end with the bigger gaps between the stones. So we had low expectations of the outcome.

We just wanted to finish it so we could have our weekends back.

But as we started doing this final step, the pebbles suddenly “tied the room together.”

The bluish pebbles brought out all the nuanced colors of the flagstone. And the gaps suddenly didn’t seem like mistakes. The unusual shapes made the overall look even more special and distinct.

Initially, I thought it would be difficult to add the pebbles in the smaller cracks. But using a flat wide shovel, I was able to lay them in very easily while my wife came behind me and leveled out the pebbles by hand.

One thing we didn’t do was add edging. That can help to keep the pebbles (or whatever other filler you use) from spreading out over time. We may add it eventually—but that seems like unnecessary fine-tuning at this point.

For now we’re just happy it’s finally finished. And suprisingly—AMAZINGLY—it actually looks pretty awesome.

Looking at it now, all the pain it took to create it seems like a distant memory.

Quick Update after ~4 weeks:

One thing to watch for with pavers is settling and sinking when the ground underneath gets wet—especially if you don’t dig far down enough or if your base isn’t compacted properly. I’m happy to report that we’ve had at least 2 bouts of decent rain, and the patio is not only draining perfectly, but all the stones are still level and stable.

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