Mixing & Pouring the Concrete
As I mentioned before in the materials list we purchased Quikrete Countertop Concrete Mix. Another popular brand is Cheng’s Concrete Kit found online (you purchase the additives online and add it to bags of regular concrete that you purchase from the hardware store). To be honest they both seemed like great options but we didn’t love the idea of added expense or chore of having to mix in additives. We decided we’d go with the simpler, less expensive option and ordered the special Quikrete countertop formula from the service counter at Lowe’s. There are also other fancy concrete mix options; various colors and aggregate options, etc. No matter the brand or tutorial, you will see everyone online recommends a very strong concrete mix for this project, or even better a specialty product designed for countertops!
Various trowels we used. The smaller trowel was helpful for packing in the concrete around the edges of the form. The magnesium float on the right was used for the last several rounds of troweling to smooth over the surface.
The “set up” outside. We were dealing with some rain (naturally!) so we needed to protect the bags of concrete from the water; hence the tent and tarps.
Put on “junky” clothes and protective gear (chemical gloves, eye protection, etc.) This is a (minimum) two person job. My husband was set up outside with the concrete mixer and I was inside ready to start working the concrete onto the counters.
Side Note: You will want to designate an area in your yard, driveway, etc. where you will be able to dump any unused concrete, concrete. Perhaps on top of some scrap cardboard.
Mixing: When you mix the concrete follow the instructions on the bag of concrete that you purchase! The amount of water added to the mix and the consistency of the mixed concrete is directly related to the strength of the concrete. Too much water and the concrete will be brittle/weak and prone to cracking. Too thick/dry and you won’t be able to work with the concrete to fill in gaps and you could end up with air pockets = weak concrete = cracks.
My husband mixed the concrete in small batches, 1 – 80lb bag at a time. Once mixed, he brought it into the kitchen in smaller batches using the 5 gal bucket. The concrete was so heavy that he could only bring in about a half bucket at a time (protect your back!!!).
Do a little YouTube homework ahead of time and learn how to mix concrete. Even if you think you know… it can’t hurt to refresh the memory.
Pouring: I had my trowels ready to go inside, as well as a separate 5 gal. bucket of water with a microfiber cloth that stayed wet in the bucket. When I was done with a trowel and needed to use another, I would drop it into the bucket of water and occasionally wipe off any concrete to keep them clean as I went along. Refresh the water as needed. Using clean tools makes the job a little easier.
We went from left to right working our way around the “U” shape of our counters. We started by pouring the concrete in the far corner and then I filled in working my way across the countertop surface. I used my fingers (with gloves!) to work/pack the concrete in all around the remesh and I used the small pointed trowel to pack the concrete all around the edges of the form. It’s very important to work the concrete into every nook and cranny so there are no gaps or air pockets.
Screeding, Vibrating, & Troweling: To be honest I didn’t screed a whole lot. I used a spare 2×4 to do a very rough/initial screeding (mostly to help the concrete settle in and to remove any excess concrete off the top) to get it roughly level. After the rough screed with the 2×4 I used the pool trowel to work the cement and smooth out the surface (about 1-2 passes). Screeding is another technique to research on YouTube.
Vibrating the cement helps to settle the mix and also let air bubbles rise to the top. They make fancy expensive tools for this, but we improvised. We used the orbital sander (no sandpaper, and covered with a couple of spare plastic grocery bags to protect the sander from the wet concrete spilling over the edge of the form) to vibrate along the front edges of the form. Again, this is something that you can’t really “overdo” – the more air bubbles you can get out, the better.
Finally, I used the magnesium float to work up the “creme” on the surface of the countertop periodically as it cured. Again… YoTube university will enlighten you if this sounds foreign.
- Side Note: I used a level throughout the entire process (from screeding to the final trowel) to keep monitoring the countertop to ensure it was level. Going back to planning the melamine molds… you need to make sure all of the top edges of your melamine molds are level! The edges of the form are your guide! If they’re off, your counters will be off!
If you’re interested… this YouTube video and this YouTube video demonstrates the pre-made snap off forms and it is also is a great example of how to screed and trowel.
The channel that is under the magnesium float is where the concrete will be poured at the front edge of the sink. We opted to do a new drop-in sink. Undermount sinks expose the inside edge of the countertop and we didn’t want to fuss with that. It’s easier to just cover that up with a drop-in sink!
DIY Concrete Counters:
Part 3 of 6 – Preparing the Surface
Part 4 of 6 – Mixing & Pouring
