Overview: The projects, special materials and costs
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Key table top materials
The top is made from construction
grout tinted with colorant. Tile
grout creates the dark veins.
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.
A different
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
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Photo 1: Build an upside-down form
Assemble the form, spray on lubricant and wipe off the excess. Cast upside down, the
tabletop's surface face will turn out as smooth and flat as the melamine 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.
Aluminum foil tape scrunched, straightened
and stuck to the form sides creates the edge
texture.
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
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Photo 2: Mix one bag at a time
Add grout to water mixed with colorant.
Turn a bucket into a giant measuring cup
so you can easily use the correct amount
of colored water with each bag.
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
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Photo 3: Pour a pattern
Sketch a pattern on the form and fill the
outlined areas with mounds of construction
grout. This pattern will show up on
the top of the table.
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Photo 4: Create the veins
Sprinkle dry tile grout along the edges
of the mounds. The colored powder will
form dark lines in the finished top.
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Photo 5: Blow the grout
Turn down the pressure on your compressor
and blow the tile grout against
the edges of the mounds.
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Photo 6: Fill in the blank spots
Cover the bare areas of the form. Pour
between the areas you covered first, not on
top of them. Jiggle the form to spread and
level the mix.
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Photo 7: Add the mesh
With the form about half full, lay in the
welded wire mesh for reinforcement. Then
completely fill the form.
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Photo 8: Screed it off
Scrape off the excess using a straight board and a sawing motion. Cover the wet grout
with plastic. The longer it stays wet, the stronger it will cure.
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
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Photo 9: Seal the table top
Bring out the color with sealer. Before you apply the sealer, ease the tabletop's sharp
edges with 80-grit sandpaper.
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
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
concrete mix?
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.
