This outdoor kitchen island was designed to be used as a food preparation station next to the grill. Because the island was planned as an outdoor piece, I used cedar lumber and stainless steel screws. The same design could be made using standard 2x4s and deck screws for a little less money. Even though the wood bottom looks quite intricate, it's actually quite easy to make. Only a few cross cuts are needed to create it. The assembly is done with stainless steel screws. I used grey Quikrete Commercial Grade Countertop Mix cast into a melamine form to make the top. It's as smooth and hard as stone but weighs about 200 lbs.
Cut the Melamine Board
Use a circular saw to cut three 2.5" wide strips, 4 feet long. I used the guide attachment for my RYOBI Circular Saw to get nice, even cuts.
Glue Down the Formwork
Normally, I screw melamine strips to the wood blocks, but I didn't have screws with the right length, so I tried using a hot glue gun to glue down the melamine strips. It worked quite well and also created a waterproof seal around the outside of the form.
Seal and Clean the Form
Use latex or silicone caulk to seal the form. Squeeze a bead of sealant in the corner and then smooth it out with your finger. Once the caulking is dry, wipe the form to remove dust and dirt before pouring in the concrete.
Prepare the Rebar
I wired together a rectangular reinforcement frame from 4 pieces of 1/2" diameter rebar.
Mix and Pour the Concrete
Quikrete Commercial Grade Countertop Mix is easy to work with and has no large pieces of aggregate. This mix is easier to work with, but sets up faster, so you need to work quickly. I used about 2 1/2 bags. I filled the form about two-thirds of the way full and then put the rebar in place before filling the mold the rest of the way.
Pack Down the Concrete and Vibrate the Form
Make sure the wet concrete is pack down into every corner and vibrate the form. I used a scrap piece of wood as a screed to level the concrete.
Let the Concrete Cure
Let the concrete cure for at least 48 hours before removing the form. The manufacturer suggests covering the concrete to control moisture.
Remove the Form
Unscrew the formwork and scrape off any of the caulk that is stuck to the concrete.
Cut the Wood
You can cut the wood for the base with a circular saw and a speed square, but a compound miter saw makes it a lot easier. Lightly sand the rough edges after cutting.
Assemble the Bottom Tray
Lay out the pieces for the bottom tray and screw them together. Use a square to check and make sure that your corners are at nice, 90 degree right angles.
Assemble the Top Frame
Screw the top frame together with 2 1/2" screws. I used a cut-off end of the 2x4 as a spacer and a square to make sure the frame was square and ready for the legs.
Screw On the Legs
I used 3" screws to screw the legs to the top frame. Without the bottom tray to hold them in place, they will wobble a bit, so don't worry about making them square yet.
Screw In the Bottom Tray
Flip the legs and top frame right side up and slide the bottom tray between the legs. Use scrap 2x4s to raise the bottom tray 3 1/2" off the ground. Use a square to make sure the legs are in the right position and then screw through the legs into the bottom tray with four 3" screws for each leg.
Add Additional Screws
Now that the bottom tray is in place, drive additional 3" screws through the top frame and into the legs.
Field Measure and Cut the Top Trim Pieces
Measure the width of the base and then cut two pieces of 1x4 that exact length. Screw them into place and measure the length for the long trim pieces.
Put On the Top
The concrete top is quite heavy and doesn't slide, but I put a couple screws up through the wood and into the concrete about 3/8" anyway. You can also use a construction adhesive as well. I prefer screws because they allow the top to come off for transportation.
Seal the Concrete
I used Quikrete Acrylic Concrete Cure & Seal with a satin finish to protect and finish the concrete countertop. It's easy to use and looks great!