Last week I showed you the custom vanity I built for our tiny bathroom.
The downside about a custom sized vanity? You need a custom sized countertop for it. Before buying any lumber for the vanity I thought a lot about what I’d do for a countertop. At first I wanted to do a wood top with a basin sink. However, this is in our only bathroom on the main floor so it’ll get years of abuse from Jules and other future kiddos. I didn’t think the basin sink would take that abuse very well.
With a basin sink out of the picture, I knew I wanted an undermount sink (as opposed to a drop in sink). The counter is so small, I didn’t want any extra space taken up with the lip of a drop in sink. However, with an undermount sink I didn’t want to make the counter out of wood, because wood + water = damage at some point. Having always wanted to try my hand at a concrete countertop, I thought that trying it on a small scale would be nice.
If you’re not interested in reading the process and my thoughts from making this, here are a few shots of how the counter turned out.
It isn’t perfect, but I skipped a few steps that would have given it a perfect finish. If it were for a bigger project (like kitchen counters) I would definitely have done these extra steps for a fancy look on a budget. Read on through the tutorial if you’re curious.
Okay, so now for the long part of the post where I talk about how I made it and things I learned throughout the process. There are several good tutorials out there for how to make kitchen counters, but I was only able to find one tutorial about making a pre-cast bathroom counter for an undermount sink. Ron Hazelton knows his stuff! My experience wasn’t quite as seamless as his, but still turned out okay.
So basically I just followed the video by Ron Hazelton, but did make modifications here and there. First I used melamine to make the molds. Pink styrofoam (wrapped in packing tape) made the mold for the sink and 1 1/2″ PVC made perfect holes for the faucets. I just used my hot glue gun to secure each item in the perfect placement. This is one place that gave me a less-than-perfect end result. I got my undermount sink on clearance and it didn’t come with a template. I did my best to make a template for the oval opening, but it wasn’t perfect. Unfortunately it was too big, meaning a bit of the sink showed that shouldn’t have. In retrospect if I had to be off a bit, it would have been better for the opening to be a little small. Hindsight, though, right?
To keep the concrete from getting stuck in the cracks, I used 100% silicone to caulk each joint. When that was dry I spread a thin coat of Vaseline so the mold would release easily. I know a special “concrete release agent” is available at many home stores, but Vaseline does the same thing and is really cheap. I learned this trick from when I used to make concrete stained glass stepping stones.
Next up is some metal to support the poured concrete. I found this in the fence and roofing aisle at Lowes and bent it into the right shape.
I mixed the concrete as per the instructions and put some in place.
A palm sander without sand paper works great to remove the air bubbles in the concrete. Just press the side of the sander under the mold working it around the whole piece. The vibrations bring the air bubbles to the surface. To make a better finish I should have put in a little less concrete the first time around and spent more time removing air bubbles.
Then just add more concrete all around.
And use the sander to remove air bubbles. Repeat this step until you’ve filled the entire mold.
Use a piece of scrap wood to screed the top (which will actually be the bottom of the finished piece).
Let it cure according to the instructions. I could have removed the mold after a few days, but gave it one week to cure so it would be stronger. In retrospect, sanding and buffing the top would have been easier if it hadn’t cured so long, so a few days may have been better.
The sides of the mold were easy to tap off with a hammer. I left the PVC in place because it didn’t need to be removed.
Here’s a closeup of the most bubbly part of the countertop.
I just mixed a small, thin batch of the concrete and pushed it into each hole. You can buy a special concrete patching kit at a home improvement store for $8-10, but since I didn’t have much to fill, I didn’t think it was worth the money. If I were making more than a 20″ x 22″ countertop, I would have gone that route.
I gave the patches a day or two to dry out, then sanded the heck out of it. Well, not really. I didn’t buy special concrete sandpaper, but just used the regular stuff I already had. I was only able to go up to a grit of 220, whereas online I read about people using paper as fine as 1500 on their counters. So this is another place that my counter wasn’t as professional as it could have been, but the special sandpaper costs $50+, which is more than this whole thing. Not really worth it for a small project like this.
Next it was time to finish the counter with a sealer. I used a glossy concrete sealer from Walmart (maybe Seal Krete brand?). Since this was for a bathroom counter (instead of a kitchen) I wasn’t worried about it being food-safe. I didn’t say anything about being a food-safe finish, so I would assume it isn’t. I simply rolled on four coats around the whole thing using a foam roller (allowing for dry time between coats).
With the vanity built and the counter ready, it was finally time to put it all together! I used 1×2 furring strips to act as cleats inside the vanity.
Then I cut out a sinkhole and faucet holes from a piece of 3/4″ plywood. The weight of the sink would rest on the plywood and cleats.
Before putting the sink in place, we attached the drain.
Voila! When all of this is in place, the top edge of the undermount sink should be even with the top edge of the vanity. This way the concrete countertop touches the sink, but doesn’t put any weight on the sink.
Before adding the concrete countertop, we put a thin bead of silicone caulk around the edge of the sink to act as a barrier for water. We also put a bead of caulk on the vanity, but this was probably unnecessary because the weight of the countertop (and the faucet) would keep it from going anywhere. I’m not gonna lie…putting the faucet in place was a big pain in the rear end, but this wasn’t all my home made countertop’s fault. Some of the difficulty was because the faucet, and some was because with Jules napping (and us not being able to use the loud drill or multitool right outside her room) this project seemed to drag on all day. But by the end of the day, this…
It definitely isn’t perfect, but I’m okay with that. I feel like it will hold up over time (I hope!) and every time I use that sink I get all giddy inside.
Was all of this work worth it? I’m not sure. It was really time intensive. But it was also way cheaper than buying a custom vanity top from Lowes. So for us DIYers on a budget, probably. And I know if I did something like this again, the end result would be a lot nicer. Who knows? Maybe more concrete is in our future…