We created concrete countertops for our best friends’ backyard a couple of years ago and we’ll be working on the project for our backyard this summer.
So we thought we’d share the process of how to make concrete countertops for your outdoor kitchen.
Step-By-Step Instructions for Making a Concrete Countertop Outdoors
Each step in this project is almost like a project of its own. If you really want something amazing out of this project, then you should be prepared to put the time in to do it right.
Install the Frame for the Countertop
A favorite aspect of concrete countertops is the customizability concrete brings to crafting. This feature also means there is no single way of installing the countertop frame. This walk-through is for in-place concrete countertop production, and you can find pieces that act as framing lips for your concrete countertop mold, or you can also use pieces of melamine-coated boards to create a DIY mold!
Of course I don’t have a pic of the before with just the frame but I used 1×6 boards for my outer mold making sure they were level with each side so the concrete would be level when poured to the top. I used exterior plywood as my base. I cut out a hole in the plywood for the sink and made walls around it with the 1×6 boards.
When you are installing your frame, the exact materials you will be utilizing varies, but you may find it helpful to caulk where the plywood edges meet the 1×6 boards to protect against any moisture and also ensure neat edges of your countertop. If you are not confident with caulk, then using painter’s tape can help remove messes easily by outlining your desired area before application.
Prep for Casting the Concrete
When your frame is ready to pour your countertop, it’s time to do your own preparations for your project. Before you pour your concrete, you will be placing mesh into your frame with some overhang. This overhang will allow you to reposition the mesh after you’ve poured your counter mix.
You can use wire mesh or fiber mesh. When you use wire mesh, pouring the concrete over it ensures structural durability and improves its strength. If you use fiber mesh, it increases overall integrity. We used smaller gauge metal frame that we could cut easily with tin-snips.
You should also take this time to cover the areas surrounding your project to protect them. Be it with plastic or some other protective layer, you will want something to shield your belongings from the concrete. I had just built the deck underneath and the cabinets under the counter so we used lots of plastic to protect everything. As you can see in the pic below, concrete got everywhere, but the plastic saved the day.
Mix the Concrete Thoroughly
When you are going to mix concrete, you have a few options for doing so. Whether it be the traditional wheelbarrow method or the concrete mixer method, both are great options. Every bag of concrete has a different ratio of concrete mix to water to make the product efficient. Therefore, there is no specific formula for making concrete and you need to consult the instructions for your particular brand.
It is crucial to mix the concrete properly, or you may be risking your entire project. Having concrete that is too soupy will be inefficient and messy. If the concrete is too dry, it won’t stick properly. Take your time mixing to ensure you don’t make your mix too thick or thin. We used Quikrete Countertop Concrete Mix 80 lb for our project. It has special additives to help it flow better and to minimize the air pockets. It was worth the extra money as our countertop came out perfect.
Carefully Pour Concrete In the Mold
When your concrete is mixed correctly, you’re ready to pour it in the forms. You will want the same density and amount of fullness throughout your countertop mold. Having a leveled framework comes in handy for this as you can drag a long enough flat object over it to make it completely flat. As the picture shows above, we screed the concrete with a vertical 2×4 raked across the 1×6 forms to level everything and remove excess concrete.
If you are using a wire mesh then simply pull the mesh to the center of your concrete-filled mold after you have poured your concrete.
Remove All Air Bubbles
During this, you will screed – or flatten – the surface of your concrete mix while also working to remove air pockets. Failing to remove these air pockets will seriously harm the integrity of your countertop as a hole, so it’s crucial to make sure the concrete mix is solid throughout.
To remove the air bubbles from outside the mold, you can tap the mold with a hammer. This will work the bubbles to the surface, eliminating them from your mix. If you are ok with spending a bit more money then you can rent a special tool called a concrete vibrator made for this exact purpose.
The concrete vibrator does exactly what it sounds like—vibrates the concrete mixture in a controlled way so the air bubbles can escape to the surface. It can certainly save you a lot of headache so it’s probably worth renting one and doing it right!
Our friends had a few hand held sheet sanders that we used to vibrate the bubbles out of the concrete. Take off any sandpaper and simply hold the vibrating sander head to all areas of the 1×6 form.
Let Your Concrete Cure
After you have taken the time to remove air pockets and smooth the surface of your counter, you can leave the concrete to cure. While the entire curing process takes about a month, you don’t have to wait that long to remove the mold.
While you can leave it on there for as long as you feel comfortable, you can also remove the mold/frame after a few days of the concrete setting. While there is no guarantee two concrete batches will be the same, each concrete brand should give an estimate on when your concrete is cured enough to stick together.
Remove the Frame to Finish Curing
After around 48-72 hours, you can probably be confident in being able to remove the frame without damaging the counter. While full curing of your concrete may not be completed for up to a month, the material’s strength after a short period of curing is reliable.
The exact method you will use to remove your framework depends entirely on what you used to secure the frame in the first step.
Your countertop may not seem perfect, but that’s ok—there are still some finishing steps to put the literal polish on it.
Make Necessary Changes and Sand
When the framework has been removed, you are free to adjust your project as you please. You could remove parts, make any cutouts you need, adjust the shape, or any other big changes that might need done.
After any changes, you also need to sand it. There are special concrete sanding discs that will help round off your counters’ corners to prevent injuries. In the picture above the right side of the counter was sanded, while the left side with the sink was how it looked after removing the frame.
If you notice any holes or surface voids, you can mix a tad more of the concrete mix and fill the gaps. Give it time to cure again and then sand it down to ensure that smooth, clean finish. There was a hair-line crack in the front of the sink that we had to fix. I believe it was due to not having enough wire mesh around the thinnest part of the countertop and will make sure to double the amount of wire I put in my next concrete counter.
Seal the Concrete
When you finish sanding your project, you can add an extra layer of protection to your counters post-production by sealing the concrete. Concrete seals offer different finished appearances for your counters, so you have some customization choice at this stage.
Simply find a seal you like and follow the instructions from the manufacturer. Each seal has it’s own application and cure times, so you’ll need to consult the manual for the specific one you purchase.
Sealing your concrete countertop properly protects them from the weather, any potential scratches, and food stains. Remember, concrete is very porous, so it’s also crucial to seal it properly, especially in a kitchen setting where bacteria can breed easily in the porous, untreated concrete.
The last thing you want is for your hard work to be ruined the first time you spill BBQ marinade on it!
Creating a Concrete Countertop for Your Outdoor Space
Once the last coat of sealant has dried, then: congratulations! You now have a stunning centerpiece for your outdoor kitchen.
As time goes on, just remember to keep an eye on the sealant and watch for any chips or cracks. Depending on your climate, level of use, and the type of sealant you used, you may need to reseal every season or every few seasons.
Be sure to checkout what outdoor kitchen cabinets are made of, as well as learn how you clean you concrete patio to get your outdoor kitchen area looking sweet. If you’re looking into a new project learning how to make frog pond is something you maybe interested in.