DIY Fluted Concrete Table + Tips I Learned From Screwing Up Twice

Thursday, October 19, 2023 -

*This video is sponsored by DAP Products and contains affiliate links.

I needed a little table to fit between a pair of chairs in our primary bedroom. I couldn't find exactly what I wanted, and I had a few bags of extra concrete laying around from installing our Horizontal Wood Fence, so I decided to make my own. 

I've worked with concrete quite a few times before (Ombre Lamp, Floating Steps, Colored Concrete Planter, Angled Entryway Steps), but even with a decent amount of experience, I still made a huge number of mistakes. I suggest watching the full DIY, instructional video below if you want to watch me truly make a fool out of myself. Keep scrolling to learn the 11 useful tips I learned and how I finally made my own modern, fluted concrete end table. 

Tip #1: Cut Cardboard Form Tubes on a Table Saw for Cleanest Cut

Concrete form tubes are frequently used for things like post foundations, but they are also a good option if you'd like to cast a freestanding, cylinder shape. 

In order for my end table to sit flat, it was important for the sidewalls to be perfectly perpendicular to the bottom and top edges. I found that I was able to get a clean and straight cut easily by butting the cardboard tube up against the fence of my table saw while carefully raising the blade and rotating the tube. You can see what I'm talking about best in the YouTube video. 

Tip #2: Cork Underlayment is a Cheap and Flexible Option to Make Curved Forms

I bought a whole bunch of 1/4" cork underlayment to experiment with as a wall covering. The project was a fantastic disaster, but I now have a ton of thin, flexible cork I don't feel bad wasting. 

It's quite easy to bend and soaks up glue really well, which made it perfect to laminate into a ring shape. I used the ring at the bottom of my concrete form to create a recessed, toe-kick area. 

Tip #3: Pool Noodles Make a Great Filler to Reduce Weight

We all know how dense and heavy concrete is. I calculated the amount of concrete needed for my 12"x18" table and if the entire thing was solid, it would have weighed closed to 150lbs! 

I put together clusters of foam pool noodles and stuffed them inside my cardboard tube before pouring the concrete. After the concrete was cured, I removed the noodles which created a void, saving over 30lbs of weight. 

Tip #4: It's Important to Create a Waterproof Seal

One of the ways to ensure your concrete sets up as strongly as possible is to make sure it cures slowly. That means, not letting too much moisture escape too quickly. There are different ways to achieve this: by mixing in an additive, covering the surface with plastic, misting the surface, and probably most importantly, making sure your concrete form is water-tight. When I attached the cardboard and cork tube to it's melamine base, I made sure to use a high quality sealant, like DynaFlex Ultra

My go-to, heavy-duty, waterproof sealant is DynaFlex Ultra by DAP. Typically used for exterior applications, it creates a tough, hydrophobic surface that's paint ready in one hour. Once dry, it's 100% waterproof. I trust it so much, it's what we used to seal the windows, doors and siding on the exterior of our house.

Tip #5: Take the Time to Level the Form Before Pouring

Even thought it might seem like it, your garage or shop floor is likely not level. Concrete slabs are almost always graded with a slight slope to allow for drainage. Whether you're working on the floor, or even your workbench, it's a good idea to level your worksurface before pouring concrete into a form. 

Tip #6: When Mixing Concrete, Add Water First

Something I like to do whenever I'm mixing concrete is to start by adding at least a small amount of water to my mixing vessel first. I find I can avoid clumps better this way, especially at the bottom and corners of the vessel (AKA wheelbarrow). 

Tip #7: Concrete Can be Easily Shaped Once Dry but Still "Green"

Even after concrete has set up and feels firm to the touch, it isn't fully cured. Depending on the density of the mix, environment and moisture content, concrete can take weeks to fully cure, but even if it's not fully cured, with smallish pours like this, it's typically fine to remove a form within a day or two. Luckily, green concrete is still soft enough to subtly shape. For example, it's common to have a small, sharp ridge remain on the top edge of a pour which can be easily cleaned up with a steel putty knife. At this point, shaping concrete is similar to working with unfired ceramic. 

Tip #8: Quarter-Round Moulding Can be Paired up to Make a Half-Round Design

PVC trim is perfect to use for concrete forms since it doesn't absorb water. To attach pieces of trim together, it's important to use the right adhesive. Luckily, my treasured RapidFuse All Purpose by DAP is designed to work perfectly on PVC. 

I used RapidFuse to connect pairs of quarter-round strips together, outer face to outer face. This created a series of recessed, half round channel. Once the form was filled with concrete and allowed to dry, I was left with a modern, vertical, fluted look. 

Tip #9: Take Your Time to Agitate the Concrete

To ensure proper compaction and get a smooth surface finish, it's important to agitate your concrete shortly after pouring. My favorite method is to hold a reciprocating saw (without a blade) against the form. You'll notice the intense vibrations causes air bubbles work to the surface. 

Tip #10: Don't Freaking Rush!

Waiting for glue to dry is about as fun as watching paint dry. After attaching the PVC trim to the inside of my cardboard tube, I rushed and didn't allow the construction adhesive to fully dry. It didn't seem to move too much while pouring the concrete so I figured everything was okay. I didn't take all the extra moisture into consideration, which basically prevented any further curing to happen. When I pulled back the tube form, I was devastated to realize EVERY. SINGLE. PIECE. of trim was imbedded in the concrete. I ended up having to dig each strip of trim out with a chisel. It wasn't fun and ruined the entire table. DON'T RUSH! 

Tip #11: Cork Underlayment (once again) Makes a Great, Cheap Pad to Protect Floors

Once again, I'm trying to find good uses for all that cork underlayment. You can purchase 6mm cork underlayment from Home Depot for only $1.20/sqft. I decided to cut out circles of cork and glued them to the bottom of the finished concrete table. 

Ready to see the final result?

It took me a few tries to get it right, but I love the final result. Even Bogi approves. 

If you like any of these tips, make sure you pin the image below to save the idea for later!

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