Overview: The projects, special materials and costs
Like a lot of my other projects, this one was inspired by sticker shock. While I was wandering through a garden center, a stone table caught my eye. It was beautiful and low-maintenance and would last a lifetime. The only trouble was the price: $650 (on sale!). As usual, my solution was to build one myself.
My version isn’t real stone, but it fools most people and has all the durability of stone. My total materials cost was just under $150; about $110 for the top and $40 for the pedestal. Everything you’ll need is available at most home centers.
kind of grout
Construction grout is used mostly for heavy construction projects like anchoring steel columns. But it’s also perfect for casting projects because it has a creamy consistency that takes on the shape and texture of the form almost perfectly. Use a smooth form and you’re guaranteed a smooth, uniform tabletop. Most home centers carry construction grout in 50-lb. bags, which cost about $13. (Quikrete Precision Grout and Sakrete Construction Grout are two brands.) If yours doesn’t, go to quikrete.com or sakrete.com to find a dealer. I darkened the grout by adding cement colorant to the water (see Photo 2 below).
Step 1: Build the form
Plastic-coated particleboard (called “melamine”) is perfect for form work because it’s inexpensive and smooth. Cut the form base to 31-1/2 x 31-1/2 in. and then cut 2 x 32-in. strips for the form sides. Attach the sides to the base as shown in Photo 1. The overhanging sides make dismantling the form easier; you can just whack them loose with a hammer. Coat the form with spray lubricant (Photo 1). Important: Use a lubricant that dries instead of leaving an oily coating. The label will say something like “leaves a dry film.” Liquid Wrench Dry Lubricant is one brand.
Next, grab a pencil and sketch a random pattern on the form outlining the areas you’ll cover with grout first (Photo 3 below). The pencil lines will determine where the dark veins appear in the finished top. Set the form on a sturdy work surface and level the form with shims. Construction grout is slushy and will overflow if the form tilts. Spilled grout will leave stains, so cover the floor with plastic drop cloths.
Forming a Crinkled Edge
Smooth edges on the tabletop are fine, but a crinkled edge will give it a more natural look. To start, cut four strips of aluminum foil tape about an inch longer than the form sides. Then, scrunch it up, straighten it out and stick it to the form sides.
Step 2: Prepare and mix the table top materials
Mixing and pouring the construction grout is a three-phase process: You’ll use most or all of the first bag to pour a pattern (Photo 3 below), the second to fill in the pattern (Photo 6 below) and the third to completely fill the form.
Turning a bucket into a giant measuring cup (see Photo 2) will let you add equal amounts of water and cement colorant to each of the three bags without measuring each time. First, measure the correct amount of water into the bucket (I use 4.5 liters per bag) and mark the water level on the bucket. Measure in more water to locate the other two marks (at 9 and 13.5 liters).
Next, empty the bucket and dump in the cement colorant. Much of it will remain in the bottle. To wash it out, pour in a little water, shake hard and pour again. Repeat until all the colorant is washed out. Refill the bucket with water and you’ll have tinted water, pre-measured into three equal amounts. The colorant tends to settle to the bottom, so stir the colored water before each use.
Construction grout hardens fast. In warm weather, it will become stiff and difficult to work with in just 15 minutes. Minutes wasted cutting the wire mesh or searching for a tool can ruin the project. So have absolutely everything ready to go before you start mixing. It’s best to have a helper, too. To slow down the hardening, use cold water only.
Mix the construction grout in a plastic cement tub. Don’t pour the water directly from the bucket into the mixing tub; it’s too hard to control the flow. Instead, ladle the water into the tub with a smaller container. Dump in about half the bag and mix it thoroughly. Gradually add the rest of the bag as you mix. If the mixed grout stiffens before you can use it, stir it to restore the slushy consistency. If it becomes too stiff to stir, toss it. The tabletop only requires about 2-1/2 bags, so you can afford to waste some.
Tip: Buy one, get one cheap. You can cast a second tabletop using mostly leftover materials. The only thing you’ll need to buy is more construction grout ($40).
Step 3: Pour the top
Photos 3 – 8 show how to complete the top. Don’t forget to turn down your compressor's pressure to about 5 psi before you blow the tile grout (Photo 5). Cut the 2 x 2-ft. section of mesh (Photo 7) using bolt cutters. Wire cutters won’t do the job.
Step 4: Remove the form and seal
Resist the temptation to tear off the form as soon as the grout is hard. The longer the grout stays wet, the stronger it will get. Give it at least three days. A week is even better. To remove the form, get a helper and flip the form upside down. (Don’t let the top tip out of the form!) Then knock the form sides loose with a hammer and lift the form off the top. Don’t despair when you unveil the bland, gray top. The sealer will deepen the color and accentuate the black veins (Photo 9). Most sealers can’t be applied until the grout has cured for at least 28 days. Before you apply sealer to the top, try it on the underside to make sure you like the look. I used a glossy “stone and tile” sealer to bring out the most color. A sealer with a matte finish will have a subtler look.
Figure A: Pedestal Details and Materials List
The tabletop height is 30 in. The top itself is 30 x 30 in. and 2 in. thick.
To cut the half-lap joints, set the cutting depth on your circular saw to 1-3/4 in. Cut a series of kerfs no more than 1/8 in. apart. Break out the slices with a hammer and chisel. Fasten the top to the pedestal with eight concrete screws. Construction grout is easy to drill; you don’t need a hammer drill. Wrap tape around the drill bit to mark the depth, and be super-duper careful not to poke through the top.
Note: You can download and enlarge Figure A: Pedestal Details along with the Pedestal and Table Top Materials lists in “Additional Information” below.
Frequently Asked Questions
Can I make it bigger?
Yes, but remember the weight factor. I once made a 3 x 5-ft. tabletop from construction grout. Moving it was like a scene from “The Ten Commandments.”
What about other colors?
Home centers typically carry three or four colors of liquid colorant, and you’ll find a huge range of powdered colors online (search for “cement colorant”). I’ve done dozens of color experiments and have learned one big lesson: Coloring cement-based products is tricky. The results I got were sometimes good, sometimes bad, but always a surprise.
Why not use standard
You can. But don’t expect to get the same look you’ll get from construction grout. With concrete, you’re likely to get a rougher surface with more air bubbles and craters. That’s not necessarily bad, just different.