Concrete Patio Table with LED Lighting
I've been pretty fascinated by concrete DIY projects lately (sinks, kitchen countertops — you name it!). When I stumbled upon this nifty table from DIY Pete, I knew I had to make it.
Except for a few snags along the way (which I'll get into later), this was a pretty straightforward process and cost-effective build. The patio table is super sturdy and looks swanky, especially at night. I'm in love with how it turned out. 😍
The Finished Result
About The Build
The general process for molding a concrete object is:
- Make a mold out of smooth, non-porous material such as melamine-coated particleboard (this is what most shelving is made of)
- Silicone the edges of the mold so concrete doesn't leak
- Add inlays using styrofoam or another non-porous material that's easy to break apart with a sharp object (this could be, for example, a cylinder that would become the drain in a concrete sink)
- Pour and screed the concrete
- Vibrate to remove air bubbles
- Let the concrete cure under plastic wrap to keep it hydrated, or as recommended by the manufacturer
- Once the concrete has cured, release the mold
- Sand it
- Seal it
- Deliver it 💸
For more details, I highly recommend this Family Handyman guide:
Sounds easy enough, right? It is, but there are a few things I wish I had known going in, and some workarounds I discovered along the way.
Tips and Lessons Learned
- You do not need to use melamine for your concrete mold. Any non-porous smooth material will do. In my case, I couldn't fit the large 4' x 8' melamine sheet in our car and the Lowe's associate was not willing to cut it down for us. I was told that their saw doesn't have a carbide tip, so they won't cut through melamine (or other plastics or vinyl). Instead, I used a small 48" x 32" dry-erase board which I mounted to a 2x4 frame, then framed the perimeter with 1.5" wide PVC trim. I'm sure buying a dry-erase board isn't as cost-effective as a melamine sheet and is heavier given the additional frame you have to build, but if you're making a smaller 24"x38" slab like I was, that's not a big deal. Another downside is that, because the dry-erase board I used was only 1/8" thick, I had to screw vertically through it into the frame. This meant concrete would leak into the vertical screws, so I had to either tape over the screws or clean them out before the concrete set. Much easier to screw in from the side, with horizontal screws, like you would with a sheet of melamine.
- Always use styrofoam or another breakable material to mold inner objects. I thought I was so clever when I used a 6 oz. tomato sauce can for the umbrella hole, since it's a perfect 2" diameter (the standard umbrella hole diameter). I wrapped the can in duct tape, thinking I could bend the circumference and dislodge the can after the concrete had set. Nope! That thing is stuck in there for life. I wound up hiding the opening with an umbrella cap and removing as much of the metal as I could. Ideally, I would have used styrofoam, which breaks apart easily with a knife.
- Use a styrofoam inlay to reduce the weight. This is a great tip from my all-time-favorite show, This Old House. Use a piece of styrofoam to cut down on unnecessary weight. I wish I had known this trick before diving into this project — especially since the tabletop I made is ~150 pounds — but only saw this fantastic video after the concrete had set:
- Roll out air bubbles as you go and patch up surface imperfections later. I spent a long time (2 hours? 3 hours?) removing air bubbles by whacking the frame with a rubber mallet, slapping it with a bladeless reciprocating saw, and shaking it with a padless orbital sander. I thought I was all set to have a void-free concrete slab. And yet, when I first removed the mold, I saw several air pockets that I then had to patch. 😬 Going forward, I'm going to try the low-stress This Old House recommendation you see in the above video: Spray in your top coat of concrete, then roll over subsequent layers to remove air bubbles. Expect surface air holes that you will fill up later.
Materials
Table Base
I used about the same amount of wood for the table base as the above DIY Pete tutorial uses. My table was bar height, at 41" tall, and had a smaller surface area.
After sanding, I stained and sealed the wood with Valspar's canyon brown transparent exterior sealer. On top of looking great, the application was a breeze. It only requires a single coat and is water-ready in four hours.
For the LED lights, I bought a two-pack of AA battery-powered LED strips with remotes and various light modes, then mounted the remotes with Velcro. The circular battery pack diameter is slightly larger than the 3.5" required to sneak behind the table base's 2x4s, but you can't see it at all. I loaded the battery packs with rechargeable AA batteries. 🕺
Concrete Mold
Instead of using melamine for the concrete mold, I used dry-erase board and 1.5" wide PVC trim as discussed above.
We had insulation lying around which I used for most of my inlays (like the coasters), though any styrofoam-like substance would do.
I also used a 2" wide tomato sauce can wrapped in duct tape to mold the umbrella hole, but would recommend using styrofoam or another easily-breakable substance instead as discussed above.
Concrete Mixture
The final tabletop is 1.5" high, 24" wide, and 38" long. I used two 80-pound sacks of Sakrete 5000 and had several cups of concrete left over. In future, I'd probably mix my own elements as suggested in the This Old House video above or use a premixed countertop mix, which seems to have much finer grains that are easier to work with. This is something I'd like to experiment with.
To darken the countertop, I used one 10-oz. jar of charcoal Sakrete cement color. They recommend using one jar per 80-pound bag of concrete, but the store only had one charcoal jar in stock. So, my tabletop came out more blue-grey than charcoal.
To seal the tabletop after sanding (outdoors, with a dust mask ✅), I used Cheng food-safe concrete countertop sealer. This really kicked things up a notch and made the surface so sleek to the touch. 💆 I sealed it about five times.
Acrylic Cutouts
I used 1/4" thick plexiglass. Word of caution: Cut the plexiglass outside! Plexiglass is surprisingly smelly when you cut it with a power tool like I did.
Final Thoughts
I've definitely caught the concrete bug. I've already started dreaming up plans involving a white concrete bathroom vanity countertop (sneak peek below!) and redoing our kitchen counters. This will not be the last concrete post on this blog, I'm sure of it. 🍹