(We did a poured in place countertop, so part of the form stays in place and is part of the finished countertop.) To create the form, we used 3/4 inch melamine, which has a water resistant coating. Our form was built to accommodate a 2 inch thick countertop. This depth includes the 3/4 inch melamine. Total concrete thickness will be 2 inches at the front for the overhang and 1 1/4 inches from the overhang back.
Step 2: Profile of Form
This drawing gives you a profile view of the form so you can visualize how the edges of the form are constructed, and how the lip to your countertop is created. If you are not using the decorative rubber edging and having a straight edge, you'll want to bring in your form and just allow for an inch and a half of overhang all the way around.
Step 3: CutOuts
Be sure to allow for all cut outs (sinks, below counter soap dispensers, faucet plumbing, etc) when constructing your form. We marked our faucet and soap dispenser cut outs with the necessary sized tubing and pipe.
Step 4: Check Level
Keep check on all portions of the form being level
Step 5: Extra Features
Don't be afraid to customize your countertops with additional features. We accommodated for a built in cutting board by welding a frame out of angle iron. We positioned and scred directly into the base of our frame. This will allow for our cutting board to be removable.
Step 6: Routered Edge & Taping
Follow the diagram from step 2 to build the edge forms for your counter. Use a router with a half inch round over bit on the edge of your 3/4 inch melamine that makes up your counter base. An unroutered 90 degree angle would create a stress point and increase the likelihood of cracking. Cover exposed wood with tape.
It is important to cover any areas where the wood underlying the melamine is exposed. Uncoated or uncovered wood would absorb the water out of the concrete and cause it to become brittle and more susceptible to cracks.
We used a combination of painters tape and duct tape depending on what we had available. Focus on routered edges, joints, screw holes and where two pieces of melamine meet.
Step 7: Decorative Edge
Secure Decorative edging to the inside of the edge frame. Hold in place with a few screws from the outside of the frame. If not using the decorative edging, you would want to bring in your frame to allow for just an inch and a half lip as stated in step 2.
Step 8: Raw Form
Form for countertop built and ready for reinforcement.
Step 9: Rebar Reinforcement
Begin reinforcing your frame with 3/8 inch rebar. Bend the rebar around cutout sections that will need extra support, like the sink area. Corners off of things are your most likely places to get cracks, so reinforce accordingly. Run a piece or two down the center depending on the width of your frame.
Step 10: Mesh Reinforcement
Top the rebar with a layer of chicken wire and secure the rebar to the chicken wire with rebar ties or steel wire. The goal is a layer of chicken wire floating midway through the concrete, which will add a layer of strength to your countertop.
Step 11: Cement Mix
Mix the concrete. We used a budget friendly cement mix (pro finish quickcrete 5000) mixed with portland cement to create the look we wanted. The ratio we used was 2 quarts portland to one 80 lb. bag of quickcrete. We used an electric mixer and mixed small batches at a time and hauled in, in 5 gallon buckets.
There are lots of different options and decorative additives you may wish to add to your mix, so don't be afraid to do some research and explore the possibilities.
(If you are very particular with getting a perfectly smooth, tight pore look, you can explore using the more expensive countertop grade cement mix which has more polymers in it.)
Step 12: The Pour
We started at one end and worked our way down. We tried to evenly disperse the mix throughout the frame.
Step 13: Working It In
Using your trowel, be sure to work it into all the edges and corners as well as under and around the rebar and chicken wire. You want the cement to be level with the top of your form.
Step 14: Vibrating
Once your counter form is filled and smoothed, use an electric palm sander (no sandpaper needed) to vibrate the edges and the under side of your counter. This will assist with getting the concrete to flow to all areas of the form and release air bubbles.
Step 15: Leveling
Smooth out the surfaced air bubbles with the trowel and double check to make sure all is level with the form.
Step 16: Colorful Additions
You can be very creative with the additions you make to your countertop for additional design and interest. We wanted to add some color and sparkle so we turned to old green wine bottles.
Step 17: Crushing
Place one wine bottle at a time between a thick, heavy towel and hammer into the desired size pieces.
Step 18: Adding Glass
Wait for one to two hours (or until the concrete starts to get stiff) before sprinkling glass (or other objects) onto the concrete surface. Scatter glass randomly or in a desired pattern. Be careful to keep all glass pieces separated. If you have the glass piled on top of each other, the cement mix can't work it's way around all the pieces and you run the risk of them popping out later.
Step 19: Troweling In
Press the glass gently into the concrete and trowel in carefully to smooth. You will have a very thin coat of cement mix over the top and won't be able to see any glass when you're finished. Let cure for 5-7 days before removing edge forms and polishing.
Step 20: Revealing Glass
After 5-7 days, you can remove all of your outer edge forms. Unscrew the supporting edges and remove the decorative rubber edge.
You're now ready to reveal the glass surface using a 5-inch wet grinder. You start with a diamond wheel and then work your way through the various grits. This type of grinder attaches to a water source and a shop-vac, so the surface is wet as you work and all extra water is being sucked away as you work. You'll be doing a lot of dumps with the shop vac to empty water as it gets filled up.
Cover floors, windows and cabinets with protective coverings, it is a slightly messy process.
Step 21: Wet Polishing
Your first pass is with a diamond pad and this is where you'll see the most amount of change. Keep moving over the surface until you've gotten the desired amount of 'reveal' and then begin working your way down to the finer grits to continue smoothing and polishing. A good sign that you are ready to move on to the next grit is when the water starts running clear. Trust your eye and use the touch of the surface as your gauge, too.
Step 22: Uncovered
Once you have the surface to your liking, it's time to let it set for a few days to dry out. (It's important to note that the results can be slightly unpredictable and with the nature of cement mix, there may be variations and irregularities. Embrace the character and charm that any variations bring to this rustic type of application. You want it to be completely dry before moving on to the sealing/finishing step.
Step 23: Seal
When the surface has completely dried (2-3 days), it's time to apply a sealer. We used a 'green' penetrating sealer followed by a coat of beeswax.
Step 24: Buff
We then used a car buffing pad to buff the wax and give it a natural sheen.
Step 25: Completion
Love, Love, Love it. The process was as much fun as the end result. It cleans up beautifully, doesn't show the dirt and is easy to maintain. Try it, you'll like it!