The very first step in pouring our own concrete countertops was contacting the supplier and calculating how much material was needed for our project. All of the consumable materials except the sand, portland cement, and water came from a company called Fishstone. (The more specialized tools like the sprayer hopper & compacting rollers also came from this same company.) Once we had received our order, we needed to make sure we had all of the other materials needed for the pour: this included everything for the templates, forms, & tools for mixing the concrete.
The second step of creating our countertops was figuring out the color & thickness that we wanted and also making the templates and forms.
The suppliers suggested a two inch reveal on the sides of the countertop. For structural integrity, the countertop needs to be no less than one inch thick… so, a two inch thickness can be achieved by having a two inch edge on the countertop with a one inch thick interior section. A full two inches for the countertop is a waste of material and just adds extra unneeded weight. (The extra inch is filled with a panel of rigid pink insulating foam – also known as “foamular”.) They also suggested a certain amount of the black iron oxide to achieve a specific color. (I think this was more of a starting point for color, and less of a strict number.)
Before we started our first pour for a finalized countertop, we made mini practice pieces to see if we liked the thickness or if we liked the suggested color – we also made a test piece to see if we could make a 45 degree angle on an edge as well.
Here you can see the original suggested color on the side of the test piece as well as the darker percentage of the mix that we chose (glopped on the edge afterwards for comparison). This is also the piece where we attempted the 45 degree angle – which we ultimately decided against.
We ended up choosing a darker percentage of the black iron oxide for our mix and we also liked a one inch thickness better than a two inch thick countertop. The 45 degree angle was too difficult to guarantee adequate coverage of the material in the form without air pockets or inconsistencies, so we kept all 90 degree angles. (The 45’s would have only been for the waterfall edge on the kitchen island anyway.) Because we were going with an overall 1″ thickness, we didn’t need the pink foamular to fill out the countertop, so we returned the panels we had purchased.
After those decisions were made, we needed to make the templates for our forms.
The templates were made of thin mdf hard board panels cut into strips, aligned along the edges of the cabinets and walls, and hot glued together.
Now, I do want to take a moment for a second and talk about logistics. Transporting the 4×8 foot melamine sheets poses somewhat of a problem for us – and it was a lot more of a hassle than you would think it should be. First off, melamine is heavy and the size was awkward… and it’s just Spencer and myself. I could lift one with Spencer, but it was only for a very very short distance. Secondly, in order to transport them in our Honda Element, we needed to prop the sheets diagonally in the vehicle. Also, Element interiors seem to be made of the softest plastic imaginable for some reason: if you’re not careful, scratches galore. (In retrospect renting a Home Depot pickup truck would have been probably a good idea… but we did make multiple trips on multiple days – so, that expense would have added up quickly.)
Also, we spent time prior to purchasing the melamine, looking into alternatives: one of our countertops was going to be longer than 8 ft. and the melamine only comes in 8 ft. lengths. We had heard of people using ugly (and therefore cheap) rolls of laminate flooring as a solid surface to pour onto… but we couldn’t find anything inexpensive enough or without a texture. We scratched that idea.
Back to the forms!
Once the templates were made, we cut a melamine sheet into one inch strips for the form walls – we did this by covering the sheet in painters tape to help prevent chipping. Maneuvering a huge 4×8 foot, heavy melamine panel wasn’t happening on a table saw – so we used a circular saw. We had to be super careful to keep our cuts perfectly straight. It was also very important to make sure the strips were all uniform: later on in the process, the height of the “wall” strips helps mark the 1″ depth of the of the countertops… and therefore helps make the overall piece level.
We then set up a 4×8 sheet of melamine on sawhorses and hot glued the strips down according to the template. The hot glue is strong enough to keep the form in place (even when filled with heavy concrete) yet it is temporary enough so the form can be dismantled easily later.
One of the mini test forms. Here, you can see the edges of the form secured with hot glue:
Next, after the hot glue has set, clean the form & apply wax. (The wax is so the excess caulk pulls away easily later.) Apply black caulk to the seams of the form & smooth with a dowel cut at a 45 degree angle – the dowel will simultaneously smooth the caulk into the seams and separate any excess off to the sides. The caulk determines what the resulting corners/edges of your countertop will look like, so a smooth finish is important. Let the caulk dry overnight.
Black caulk is better to use because it is more obvious & easier to see any remaining bits you might have missed – it also acts differently than the other colors. Black and a good quality white caulk came off in large pieces whereas cheap white & clear caulk flaked and came off in little frustrating chunks.
Lastly, clean the melamine with acetone. (For some of our countertops, we needed to reuse the full size melamine panel – so we covered it in plastic drop cloths.)
- table saw
- circular saw
- saw horses
- thin mdf hardboard panels 4x8 ft.
- melamine boards 4x8 ft.
- painters tape
- hot glue gun/glue sticks
- black caulk/caulk gun
- dowel (45 degree cut)
- paper towels/plastic gloves
Here’s a list of all of our concrete countertop posts:
Part 1) Materials and tools needed
Part 2) Making the templates & forms
Part 3) Preparation for the pour
Part 4) The first stage: spraying the beauty coat
Part 5) The second stage: compacting
Part 6) finishing: grinding, sanding, coating
Part 7) installation day
Part 8) the reveal