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ARKA DIY Series: Concrete Coffee Table

I always enjoy having projects that are outside of work to get my creativity flowing. I strongly believe that stepping away from the computer and having other creative outlets really helps keep balance in my life so I can approach my job with a fresh mind and be more productive.

So, my wife wanted a new coffee table; something very specific with a wooden base and a concrete top. After looking around to buy a table for some time, my fellow designer Charles Darwizard and I thought it might be interesting to attempt to build our own table. I figured if we failed, at least it would be a good story.

I checked online for some DIY tutorials and luckily there are like 93,475,394 of them. Luckily, we aren't the first ones to build such a thing, so we decided not to reinvent the wheel and picked a couple tutorials to guide our process.

Here's how it all went down:

First you need the right building materials. For the base we purchased 3.25" x 3.25" redwood that was 10' long.
The reason why I chose Redwood was because I felt it would be stronger than Pine, and since we're putting a 250lb table top on there I had to make sure the base could handle the weight. However, I quickly learned that you can't use typical wood stain with Redwood, especially since Redwood has white and red areas that could stain differently. Essentially I would have had no idea what the end product would have looked like. I did a little research and saw that you can use semi-transparent paint that they mix for you at any Home Depot or Lowes - so we decided to go with that option. 
We wanted a pretty large coffee table since we always have people over and we like to have plenty of table space for everyone sitting in the living room. The size of the base ended being 60" long by 40" wide and 16" tall. We wanted the table top to have a thickness of 2" so the total height would be 18" which is pretty standard.
After cutting the wood and assembling the pieces with 8" lag screws, we ended up with a base that look like this:

After putting together the base, I used an orbital sander and sanded the hell out of this thing. I made sure that it was super smooth for the semi-transparent paint that I was about to apply. I applied a "boothill grey" color that would give the wood a warm gray tone, but wouldn't cover the natural wood grain. 
After painting the base, it was now finally time to work on the table top. I have never tried to work with concrete before. Luckily concrete is inexpensive. Each bag costs between $4-8 depending on what psi you get. I used Maximizer Concrete with a 5500 psi. The higher the psi the denser the concrete. For my concrete slab, it was about 17 square feet (about 3 bags). To mix the concrete you will need a large plastic tub and a rake or shovel to stir the water with. The water should be added steadily, not all at once, and keep adding water until you get the consistency of oatmeal. The concrete bag should state how much water to add per bag, but who really reads instructions anyways? 
Before playing around with the concrete you will need to build a frame that will be the shape of your table top. We used melamine as our frame base because of how smooth it is. After cutting the melamine into the frame, we ended up with this:
 The frame is 62" long and 42" wide and the depth inside the frame was 2". Before pouring the concrete into the frame, you will need to seal the corners of the frame with silicon caulking so the none of the concrete leaks through the cracks. Now that our frame was ready, you want to wipe it down with a damp cloth to make sure there isn't any debris in there. Time to pour the concrete. After mixing the concrete with the steps I mentioned above we poured half of the mix into the melamine frame, to give the structure added stability, we inserted a stucco wire mesh frame on top of the poured concrete, than poured the remaining concrete on top the the metal wire mesh. Then we proceeded to trowel the concrete. Throughout the entire pouring process you should continuously trowel the concrete to make sure that it spreads evenly throughout the frame.
 This was the first half of the concrete we poured prior to adding the stucco wire mesh. After pouring the remaining concrete and constant troweling we ended up with this:
I was worried that if we allow the concrete to dry outside, it will dry too fast and crack. To avoid this we covered it with a plastic tarp so the moisture won't evaporate too fast. Once we covered the concrete with tarp all we could do is wait. After three days, the concrete had cured and became extremely hard. 
Now it's inevitable that you will have some wormholes throughout your slab. I recommend having some mortar and mixing it with water in a solo cup and touch up the areas and scrape off the excess mortar. The next step is to sand down the surface. You want to make sure that its smooth and even. If you grind down too much you will find little bits of rocks that make up the concrete. Having some patches of the exposed areas gives the concrete some character, but if you going for the cleaner look, don't sand too much of the surface so that it look uniform throughout.  
Lucky for me, my wife wanted the distressed look so we left worm holes as is. Since the table was going to be used to entertain guests, we figured that it should be safe for food. So I used a food safe sealer made by Cheng, a pioneer of the concrete table top industry, to seal our slab. I wanted something that wouldn't take away from the raw look of the concrete but also give it a nice natural stone looking finish. So after putting a double coat of sealer, we were pretty happy with the results. 
So the final step was to place this on the base of the table. Honestly, that was the hardest part because we made such a large slab and the damn thing was over 250 lbs. Make sure you have a few friends with you because it's rather cumbersome. The good thing about the top being so heavy was that I didn't need to attach it to the base. It simply sits on top and can't really move at all. So after nearly throwing our backs out, we ended up with a pretty nice table that we could be proud of.
Before you jump into a project like this, look up a few tutorials just to get as many ideas as possible. There are always many ways to do something and see what works best for you. 
Other concrete table top tutorials can be found here, here, and here.
Buddy Bravado