DIY LANDSCAPE RETAINING WALL: OUR TOUGHEST PROJECT

Every DIY project has a point at which the DIY-er thinks to him/herself, “Why?” During this 2 year long landscape retaining wall project, we questioned our abilities and our sanity on a biannual basis. We would like to share with you our journey to completed, functional, and hopefully eternal, landscape retaining walls. Buckle up, guys.

In the winter of 2017, we had two giant trees removed from our front yard (the oldest Bradford pear I’d ever seen and a towering bald cypress). We were hoping that, since our property slopes into a dry creek bed, that the spring rains wouldn’t saturate the front yard too badly. Well, it turns out the giant trees had been drinking more than we thought, because shortly after, our basement started flooding.

After determining the floods weren’t a fluke and were happening more and more frequently, we decided to install a french drain in front of our porch. I know, seems off topic, but stay with me! Long story short, we dug a trench and installed a drain all the way down to the far left corner of our house. And by ‘we’, I mean Tyler did because I was newly pregnant!

Aaaaanyway, the french drain helped with the basement flooding, (though we still need to get a sump pump), but it did require a partial demo of a stacked stone retaining wall at the front left corner of our house. We weren’t that crazy about the stone look anyway, so we thought, “Hey, why don’t we just build ourselves a new wall! And hey! While we’re at it, let’s throw in another 10 foot long wall along our driveway! No big! Hehe!” Well, it was was big. Very big! We learned so much along the way that we would love to pass along to the internet.

We ordered VERSA-LOK Cobble blocks from a local landscaping supplier. Then, Tyler dug and dug and dug some more while I watched from the window with our newborn son. The thing about laying landscape blocks is that they have to be pretty much perfectly level. The smallest bit off and that imperfection will add up as you put down layers of blocks until it looks like a wavy mess. So that means digging down until your first course will be completely buried, making sure that layer of dirt is as level as you can get it, and then adding paver base on top of that dirt. The paver base acts as a sort of “fine tuner” because when you lay the block down onto it, you can adjust the corners and edges of the block until it’s level. We used Pavestone Patio/Paver Base.

By the time Tyler finished building the driveway wall, C was napping well enough for me to start helping with the front yard wall. And now, after experiencing it for myself, I can tell you that leveling is mind-numbingly tedious. ‘Tedious’ is Tyler’s specialty, but for me it felt like a special kind of hell. However, it is worth it to get the first layer of blocks right because it will make your wall last a lot longer. Or at least that’s what I kept telling myself when I was sooooo over it. Like, come on, we have the BURY this layer that we worked so hard on and paid money for??

But alas, on to the next row of blocks! (You’ll see the photos switch on and off between the wall in the front yard and the wall by the driveway.) For the driveway retaining wall, we used pins that stick down through the blocks. These pins hold the blocks in place but also steps them back slightly with each course. In the front yard, we couldn’t do that because of the tight radius of the wall, so we used hardscape adhesive to hold the blocks in place. We used a rubber mallet to make small adjustments to each block and an angle grinder to smooth out any lumps and bumbs. (Remember those compounding imperfections I was talking about?)

Once the main blocks were placed (can I get a HALLELUJAH!??), we started building up the gravel drainage behind the walls. This clean, 1 inch gravel ensures that water pressure doesn’t build up behind the wall and distort it. The water is able to drain down through the rock. We laid the rock on top of landscape fabric and tucked it in so that it was totally wrapped up. This keeps dirt and junk from getting in and clogging up the rock.

Next was filling in dirt behind the rock, which we had to do in layers. Couple of inches of rocks, hold it back, fill some dirt, more rocks… We repeated this until we had totally filled in behind the walls. We used a roto tiller to help us break up our very clay-heavy Missouri dirt. It made our jobs a whole lot easier! We did these layers slowly and made sure to water the dirt between layers to encourage it to settle and compact.

Once we had finally finished the main walls, (keep in mind, YEARS have passed at this point. YEARS.) we went ahead and ordered a few more blocks to add another course to the front yard wall and the cap stones for the top! We thought, “Man, this is it. We’re almost done.” Spoiler alert: This was 4 months ago.

Most people I know took trigonometry in high school but did you really, truly think you would use it in your adult life? Turns out hardscapers are also mathematicians. If you have two different kinds of walls, one with convex curves and one with concave curves, how many watermelons does Tom need to bring to Sally’s birthday party? Heh, just kidding. Hope that didn’t trigger any bad ACT/SAT memories for you.

Our cap stones are isosceles trapezoids. We started with the straightaway section of our convex curved wall and alternated the trapezoids so that they fit together in a straight line. Okay, I’m done with the trig stuff.

Tackling the curves of the driveway wall (above) and the circular wall in the front yard landscaping required cutting cap stones. Before I get into measuring the angles, let’s talk a little bit about cutting concrete.

We initially thought we could get away with a 7-1/4 inch circular saw and tried using a cheap one, knowing the dust isn’t great for motors and didn’t want to risk ruining our nicer circular saw. We knew the blade wouldn’t cut all the way through, but surely we could make it work and just cut from both sides. Pretty quickly we realized we weren’t perfect robots and the cuts never met up perfectly, leaving the sides of the stones all jagged. Wanting the sides of the cap stones to be smooth and fit seamlessly, we went back to the drawing board.

After our failed attempts at cutting with the circular saw, we finally decided to rent a concrete saw from a local tool rental company. And we were so happy that we did because, not only did this beast cut through stone like a hot knife through butter, it also had a hose hook up that threw water on the blade to keep the dust down. We were able to cut all of the cap stones in just 1 and a half days!

As for angle measuring, I will happily refer you to this YouTube video, because there’s no way for me to adequately describe it to you and we don’t want to relive trigonometry. We liked this method because it’s quick and pretty easy to do with just a speed square!

After cutting all of the cap stones, we went back through and glued them in place with the same hardscape adhesive that we used before. All that was left to do was smooth out the dirt and lay down some mulch!

We usually use black mulch because, though the color does fade over time, we really love the contrast it brings to the landscaping. Now enjoy these photos of before and after the mulch spreading!

I don’t know what makes us happier- how wonderful it turned out or the fact that it’s DONE! We’re hoping to do some planting in the landscape bed next spring. But honestly, it’s just a huge improvement as is.

I’m not sure if we’ll ever build another retaining wall after this two year long journey. I’m pretty sure C thinks that adults just build walls all the time because he’s only seen us work on this project for his entire 2 year old life. There were ups (like renting the concrete saw) and there were downs (like WHY WHY WHY DID WE START THIS? and WHEN WILL THIS BE OVER?), but all said and done, we did save a couple thousand dollars by doing it ourselves, which qualifies as ‘worth it’ to us!