Round Concrete Tables
This was an interesting round concrete table that we built for a homeowner in South Dallas. I’m saying interesting because we ended up doing it twice.
We were initially contacted by the client’s interior designer who asked us to build him a 60” diameter table but quickly changed it to a larger 69” as they wanted to comfortably seat at least 8 people at a time. They already had a nice wooden base coming from a provider in Chicago so all they wanted from us was the table top itself.
Our client wanted his round concrete table to look massive and asked for it to be 3” thick. We could build a table this thick but it would be weigh almost 1,000 lb. Instead we mold a 3” tall edge but then cut back the thickness in the center portion of the table top. By doing this we drop the weight to a much more manageable 300 lb. or so. To do this we replace concrete with wood and foam insert that stays in the middle of the table top.
We got started by first drawing a circle on a sheet of plywood that would form the base and hit our first issue. It was too big to cut out from one sheet, we would have to build it in sections and butt them up together. We wanted this base to be rigid so be installed wooden slats spanning where the sections came together, stiffening the whole assembly. To keep the weight down we cut out foam inserts and installed them between the slats.
When we added the thickness of the plywood plus that of the slats the center portion or our round concrete table was still a little thicker than we wanted by about 1/4”. Doesn’t sound like much but for a table this size that little bit ends up adding 85 lb. We picked up some sheets of masonite which is a light weight wall material and cut that into a circular shape and laid it over our wood/foam insert. Bingo! We hit our needed thickness.
Reinforcement is an integral part of concrete tables and we went with a metal lath that was screwed in through the masonite and directly into the plywood base underneath. That helps prevent any cracking, particulary when transporting the table top. Our final step prior to pouring was to use that same masonite material to form the table top edge. It’s very flexible and can be curved without snapping in two. We cut it into 3” strips and blocked it into place with wood supports to prevent the mold from blowing out during the pour.
After some math we figured out just how much cement, water, fiber, and additives we needed then got to mixing and pouring.
This was a face up pour, i.e., our round concrete table top was not being poured upside down as is traditionally done when it’s a precast piece which meant we were going to have to trowel the finish for some hours after the pour. Troweled surfaces do tend to have more personality than precast ones which are cast against a mold that creates a more uniform finish. Once the piece had cured we broke down the mold, lightly sanded it and wrapped it up by sealing with a water based polyurethane to give it a satin finish. It looked great!
Finally it was installation day for our round concrete table. Since the piece was large and heavy we took an extra guy to make sure we could do it safely. It dropped right into place over the base the client provided and looked fantastic. Smiles all around and we walked out with our check.
As we were driving back I got a call from the designer saying we were going to have to build him another one – Great News!, until he told me why. The one we had delivered was too small, it was 60” instead of 69”. I couldn’t believe it but it was totally my fault, I had worked off memory and built it based on our initial conversation. Back to the shop to rebuild, repour, and reinstall, we finally got it right the second time. Hard lesson learned – write everything down, don’t go off memory.