How to cut stone caps for a curved retaining wall [with photos]

So, you’re probably reading this because you thought creating curved stone landscape borders would be “unique and different.” And with landscaping blocks it’s pretty easy to create that nice, serpentine, curved look you’re going for. But, if you’re anything like me, you probably didn’t think about the caps that sit on top of those stone blocks. They’re not so easy to manipulate into a curved shape.

No worries though! In this post I’ll show you how to make cuts in the stone caps so you can finally finish up your project. Once you know the process for measuring/cutting the capstones, it goes pretty quickly. Let’s get to it!

By the way, this was the final step to complete this stone garden border that surrounds my foundation plantings. If you haven’t started your project yet, you may want to read that post first.

Materials Needed to Cut Stone Caps

1. Stone Caps, and the stone edging already leveled and in-place
2. Saw: We used a circular saw; an end saw would be better
3. Diamond masonry blade (high performance), about $15-$20
4. Pencils (lots of them, you will go through a lot)
5. Straight edge (I used a 12″ level)
6. Adhesive to glue the caps onto the wall.

How to Cut Stone Caps: The Process

Obviously, the process to cut stone caps for my landscape border would be much easier if I chose to do a straight line. Nothing wrong with doing a straight line of course. Even with a straight border you’ll likely need to make a few cuts along the way. But, my house is fairly boxy to begin with, so I went with a much more curvy, organic shape.

Which made for a lot of stone caps to cut along the way. Curves are sexy, though. It was totally worth the effort.

Here’s a quick look at the process.

1. Set the adjacent caps in place
2. Set the stone cap you need to cut on top so they overlap the adjacent caps.
3. Mark the underside of the stone cap you are cutting.
4. Use a saw to cut the caps.
5. Dry set the cap into place to ensure a good fit.
6. Repeat the process.
7. Glue the blocks into place.

Doesn’t sound so bad, right? It’s not… I swear.

Before we begin… just know that there are many ways to cut stone caps. This is merely one way.

Step 1: Set the adjacent caps.

The first step is to set every other stone cap onto the wall. It probably sounds counter-intuitive… right? Well, following my process will save you a bunch of time. So, set your first stone, then leave a gap, then set your next stone. The trick is to leave enough space in between the two blocks so that a third block will overlap on each side when you set it on top.

By the way, we’re just dry fitting these. Don’t glue them down or anything… yet.

Why would you do this, you might be wondering? Well, you’ll be able to cut the same stone on both sides, rather than having to make cuts on every single block. Basically the goal here is to cut every OTHER stone.

So, every opportunity I had, I cut ONE stone on TWO sides, rather than making cuts to both sides of every cap. This definitely saved me time and it turned out really nice!

Make sense?

Step 2: Set the stone cap you need to cut on top.

Next, you’ll set the stone cap you’ll be cutting on top of those other caps you just laid out. Make sure that it’s overhanging on the left, right, front and back. No gaps at all or this won’t work out.

You could do this all the way along the length of your retaining wall or stone border. But… it’s probably not going to work out exactly like you planned. Although it will take more time, you’re going to get a much better fit if you cut these blocks one at a time.

So now that we have the capstone in place, onto the next step.

Step 3: Mark the underside of the stone cap you are cutting.

You’ll need a pencil or some sort of marking device to do this part. We’re going to make the marks from underneath the block that’s sitting on top. Lucky we have a bit of a gap to reach into, right?

To make this as easy as possible I’ve broken it down into four steps.

1. Mark the front and back on the right and left sides from underneath. Basically you’ll make a mark where the overhanging cap meets the other cap , so that you get a snug fit. Do this on the front facing and back side of your block.
2. Now remove your block and flip it over so you can see the faint pencil lines you just made.
3. Use a straight edge to connect the front and back lines. See.. curved retaining wall with straight cuts! Amazing!
4. Finally, you will have solid cut lines so you know where to cut the stone.

Step 4: Use a saw to cut your blocks.

So we’re finally ready to make the cuts. And guess what, they are straight cuts, even though the wall is curved. This kind of blew my mind when I thought about it.

I made my dad do this part because, well, wouldn’t you if he offered?

Cutting the stone caps is extremely, extremely dusty. Use protective eyewear. Seriously, even if you are watching your dad do it, you still need eyewear.

Cut the caps with your pencil marks facing up.

Spraying a hose at the blade while using the saw will cut down on the dust. So, you may need to bring a friend into your DIY project or make your kid stand there and spray with the hose. It will help for sure.

And… a word of caution. It’s really loud, so don’t do this at 6AM so that all of your neighbors come sleepily stumbling out of your house wondering what all the racket is. Not that I would know…

Another word of caution: make sure that your neighbors don’t have clothes hanging on the line to dry when you do this. The dust will be a magnet for their wet clothes. Not that I would know….

Step 5: Dry set the stone cap into place.

Once your stone is cut to size, it’s time to set it into place to make sure that it fits!

Look at that… it’s a perfect fit.

Depending on the tightness of your curves, you may also need to cut the back area to make the face of your stone line up with the others. I had to do this a few times. By “I” I mean my dad had to.

Overall, if you choose a style that has a little wear and tear/tumbled look to it, the minor imperfections become quite charming. I’m a believer that nothing is ever going to be perfect and strive to set myself up for SUCCESS in my projects. In other words: don’t sweat the small stuff.

If you’re happy with your first cut, we’re ready for the next step!

Step 6: Repeat the process.

Slow and steady wins the race here. I did this one block at a time so that I had a really nice, tight fit.

You can see that for the most part I had to cut every other cap. I just kept a slight overhang for some added interest on the “tiered” parts. 

These are all just “dry fitted” for now.

Step 7: Glue the blocks into place.

After you’ve cut everything and dry-fitted it, you’re ready to do the final step: glue the blocks into place. This is a good idea if you want the wall to stay looking nice.

In full transparency, I didn’t glue mine into place for like… 6 months. I might have been longer…. it was a really long time. And, I bumped them with the lawn mower like every time I cut the grass because I’m a bull in a China shop. So, I was forever fitting them back into place and creating all this extra work for myself.

So, the moral is… if you take the time to cut stone caps, take the time to glue stone caps. Use an adhesive like Liquid Nails landscape block, stone & timber adhesive. When I finally got around to gluing them down, this is what I used.

In the end, this is how it turned out. What do you think?

Overall this wasn’t a difficult project to do… other than cutting the blocks with the saw because you need two people and it gets so dusty. But all in all I think it’s pretty neat that you can make straight cuts and turn them into a curved wall!

Also… if you haven’t laid the other blocks yet be sure to check out my post on leveling and setting the stone border. You’ll need to do that, first, obviously!

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