How to Pour a Small Concrete Slab

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This past weekend, I laid a new DIY concrete slab will serve as a spot for hiding the city’s ugly trash bins from the street and help with curb appeal. In today’s post, I’ll show you how I did it step by step!

Like a lot of you (probably), I keep a running tally of projects in my head, often prioritized in a number of ways:

• the stuff that needs to get done for financial reasons (either opportunity cost, lining up sponsors, or actual dollars)
• the stuff that needs to get done for sanity reasons (aka, things that make my eye twitch)
• the stuff that needs to get done because they’ve been on my to-do list for way too long (“slacker projects” as I like to call them)
• the stuff that I elected to do as a distraction from one of the first 3 reasons above (usually a result of some kind of frustrating setback that made me want to cry/curse)
• and so on…

As far as “lay a concrete slab for my trash bins so I don’t have to look at them in the driveway anymore” goes, this project checks multiple boxes. I absolutely hated the aesthetic of that bright green can and recycling bin in front of the garage door. And when you consider the number of exterior changes I’ve made for the express purpose of giving my house more curb appeal, leaving the trash bins out in the open just wasn’t going to cut it anymore.

Sure, I could drag them to other parts of the property — such as behind my (now-repaired) backyard fence or put them in the garage — but after seven years of living in this house, I couldn’t seem to get myself out of the habit of doing the bare minimum. I even asked you guys for new ideas last spring, only to find myself in the same habit.

By putting it on the side of the house with a wood screen, I figured this would be a win-win for the part of me that wants the bins to be hidden and the other part of me that really doesn’t want to drag them across the lawn or include them in my backyard makeover plans (to those of you who say “put them in the garage,” you either aren’t familiar with what Georgia heat can do the smell of an outdoor trash can, or you are very optimistic about the availability of spare square footage in the one-car garage of a serial DIYer).

To make my solution happen, I would need a small, flat area — and since I was going to (hopefully) build a new shed in the back yard, it seemed like the perfect opportunity to hone some new concrete slab-making skills.

How to form a concrete slab

Last fall, I got as far as digging out the spot for the slab, creating the frame, getting it level, and filling it with pea gravel. Higher-priority projects distracted me enough during the winter to make me procrastinate on the next steps, but with weather warming up, I was anxious to get this done!

I’ll start from the beginning in case you never saw that post, so this list includes everything.

Recommended Tools & Supplies

• scrap 1×4 or 2×4, cut to length
• wood stakes (or you can DIY your own from scrap)
• miter saw (this one’s mine)
• right angle corner clamps (think of it as a shortcut to getting a square frame)
• screws
• drill (this is mine)
• pea gravel (or other gravel, but pea gravel is cheap)
• level (this is one of mine)
• rigid rake
• tamper tool (optional but very useful)
• shovel
• high strength 80 lb. concrete mix
• wire mesh / hardware cloth
• tin snips
• protective gloves
• wheelbarrow
• water hose

Building the frame is really simple, but using a set of right angle corner clamps is a nice hack that saves me from a lot of frustration.

Step 1: Call before you dig

Word to the wise: before digging, call 811 to have your utilities marked off. Even if you don’t need a permit for the actual project (in my county, since I was doing something that wasn’t attached to the house directly and was less than 32 sq ft, I was fine to proceed), striking a utility is still a thing you want to avoid! If you’re building a concrete patio, check with your county as you may need a permit.

Step 2: Cut the frame and dig

While screwing the frame together, I checked for level over and over again. In all of the years of me ever trying to get things level in my house, I can never get it on the first try. And when laying a slab, you want it to slightly slope away from your house so that rainwater flows away from your foundation (about half a bubble is what I’ve read — which as the name implies, is about half of the the bubble within those middle lines). And the one time I needed a frame to be half a bubble off? It’s perfectly level. Gah!

Step 3: Pour and spread out gravel to fill the base

I poured in a couple of bags of pea gravel on the bottom and spread it out with a rake. I used the rigid tines of the rake to also compact the gravel down a bit to establish a flat base layer.

And that’s where it sat until spring (and this post).

Step 4: Gather the rest of your supplies

Next steps require heavy-duty gloves, a wheelbarrow, shovel, bags of high-strength concrete (obviously), screen mesh (arguably optional for such a small slab), and a hose.

Oh, and tin snips — if you’re cutting hardware cloth, trust me. This and gloves. They keep you from bleeding from the hand (spy the small cut on my thumb prior to putting on the gloves I should have been wearing??).

Wire mesh is meant for reinforcing the concrete, which one could argue is overkill for this project (because the slab is small, perfection was not a major concern with its intended purpose, and the concrete chosen is designed to not really need it).

For larger slabs, you’d use something like rebar or even doubled-up chicken wire (as one friend of mine suggested). I briefly considered even taking out part of my chain link fence and saving it for this, but since I had leftover hardware cloth from my big battle with attic squirrels, this would be a nice use for the rest of the roll.

But that’s enough prep talk. Let’s get to mixing!

Step 5: Mix first bags of concrete

I used the shovel to break open each bag, mixing one at a time before pouring into the frame. It’s a good workout, but also pretty easy. Add a little water, mix, more water, mix, etc. until you reach a nice consistency. You don’t want it to get too soupy, and it takes a little practice to know the right amount.

Step 6: Spread out concrete and add mesh

To spread out the concrete mix, I used a rigid-tine rake, then laid a cut piece of the mesh on top. I only did one layer of mesh (to sandwich it between the bottom and the top of the slab), and that seemed like enough. I considered a second after a few more pours, but it was kind of tough to hide the mesh, so I didn’t want to risk it when I got closer to the top of the frame.

Step 7: Add more concrete on top

See those wooden stakes sticking up around the frame? They’re meant to help make sure the frame doesn’t bow out as the slab dries. For a bigger slab, this would be much more important, but for a small one like this, the 2x4s seemed plenty rigid on their own. And since I wasn’t pouring a large slab, the depth and width of the boards was perfect. If filling the frame completely, you’ll want to saw the tops off of them so that you can run a board all the way along the frame and smooth out the top, unless you’ve got a bull float laying around. Not the tool I’ve had the interest in acquiring though.

And then, there’s more mixing.

And more spreading, and more mixing. #earnyourbeer

I bought 4 bags at first, but had clearly underestimated, so I went back to the store for more bags.

Step 8: Smooth out the top with a scrap piece of wood

Even though the plan was to fill the frame completely, as the sun began to set, I had grown really tired of the process (I actually liked the workout of the mixing part, but it was the spreading part that oddly kept frustrating me). So when I ran out of bags again (yes, I could have done the math and bought the correct number originally if I had only looked at the handy chart on the bags, but I eyeballed it like I do with many projects), I said “good enough” and decided I’d rather just screed the top and let it cure. Here you can see we just used the very innovative 2×4 method as our straight-edge. Tip: The board will try to sink so you’ll want to make sure the surface of your slab is damp (a mist setting works well), and that you’re using a sawing motion to smooth things out. My boyfriend was over to help and has some past-life construction experience, so I let him take over when I couldn’t get things the way I had envisioned. Typically if you’ve filled the frame all the way in, you’ll want to use a board long enough that it touches both sides of the frame and drag it across the concrete. This will force excess to spill out of the frame, leaving you with a smooth and level surface.

Here’s where you can really let your perfectionism shine by spreading things with a steel trowel for a super smooth finish. There’s also an edging tool that rounds off your sharp edges if that’s something important to you. Depending on your needs, if you actually want to add texture, a common way is to use a broom (aka “broom finish”), which will add traction underfoot (if you’re using it to create a walkway, for example). My only goals with the final finishing was that I had no cracks and that the cost of labor was nice and cheap.

(Also, I was getting hangry, and “Hangry Sarah” is no one’s friend.)

I let everything dry, and it was looking pretty darn good the next day!

Step 9: Remove frame (after ample curing time)

I wondered if the wood frame would stick at all, but to my surprise, it was really clean! It took all of about two minutes to remove.

Yeah, it’s not perfect. But I learned quite a lot about how to build the frame, how many bags I think I’ll need versus how many I actually do (way more), how hard it is to mix multiple bags of concrete (it’s not, really), and more, which was exactly the point.

Done!

It isn’t half as intimidating as I thought it was going to be. And since this is only for the sake of a couple of trash bins (aka: nothing requiring perfection), I can simply move on from this imperfect cement slab and focus on the other parts of this project that will make it look more finished.

And look! My trash bins finally have a home on the concrete pad. It has the convenience of the closeness of my driveway without the eyesore of sitting in my driveway, which will make the exterior before and after that much better.

Up next will be finishing the wood screen that will hide it altogether from the street (kind of like I did with the one in front of my air conditioning unit). The garden I place around it is also part of this summer’s plans, so I’ll be sharing the full before and after once all of the planting and mulching is complete.

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