How to Make a Concrete Counter Top in Place

Ron Hazelton:
As a building material, concrete has been around for a long time. But the idea of using this age old material for interior detailing like counter tops is enjoying renewed interest and enthusiasm these days.  So when the opportunity came to work alongside a  real pro in New Mexico, I went looking for homeowners who are passionate about concrete.  Take Michael Kram's house.

He built it himself and lives here with his wife Susan and their daughter Hannah.  His use of decorative concrete on the floors came out so well that Michael hired a local craftsman to create a concrete kitchen countertops.  So this is a concrete counter.
MICHAEL:
That's right Ron and I love it.
RON HAZELTON:
So how did you ever come to choose concrete for counter?
MICHAEL:
Well I was looking for a simple looking finish that's durable and has kind of like an old world look to it.
RON HAZELTON:
Now Susan, what's it like to actually use this?
SUSAN:
Well not only does it look very good but it's very practical.  EAsy to clean, right Hannah?
HANNAH:
Yeah, it's really smooth. And when you spill something, it's easy to get up because it doesn't really soak in.
RON HAZELTON:
When you spill something?  You don't spill things on this, do you?
HANNAH:
I try not to.
RON HAZELTON:
But occasionally when it happens, it's real easy to clean up, huh?
HANNAH:
Yeah.
RON HAZELTON:
Today I'm going to meet the man who built these countertops, Spencer Martin. And watch as he builds another concrete countertop in the Kram's bathroom.
SPENCER  MARTIN:
Thank you very much.
RON HAZELTON:
Well I know you've done some work here already. This started out as a - as a vanity. Can this process be done on any standard baSe, vanity base, kitchen counter base -
[BOTH SPEAK AT ONCE]
SPENCER  MARTIN:
You cAn use anything.  Ostensibly. you could use a good solid cardboard box that a refrigerator came in as long as you didn't get it wet or kick it.
RON HAZELTON:
Spencer has already installed the form or mold into which he'll pour the concrete. The  form consists of a  few different parts. To make up the bottom of the form, he attached cleats to the base cabinet and placed a piece of vinyl coated particle board called melamine on top. The vinyl surface on the melamine will allow the bottom to be removed easily later on.  He drilled 3 holes through the melamine and inserted short pieces of PVC pipe  that will create holes through the concrete for the faucet.

Next, Spencer attached 2 by 4s to the outside of the cabinet and then secured strips of melamine to them.   Constructing the form this way will provide a lip or overhang to the cabinet.  Exposed wood surfaces are covered with electrician's tape to insure they will release easily when the form is removed.

A styrofoam block cut in the shape of a sink will create the proper sized sink opening in the concrete.  Spencer applies a bead of caulk around the bottom to create a good seal. Then he secures it with screws.  Finally he sets a piece of reinforcing steel in place to give the countertop additional strength and prevent cracking.  Next we move outdoors to  mix the first of two batches of concrete.  This first batch will form the core of the countertop. Use a minimum amount of water  as a bASe mixture and Spencer blends it with a mason's hoe.

With plenty of protection on the floors, Spencer rolls a wheelbarrow right into the bathroom.  And immediately begins shoveling the concrete into the form.  He compresses the concrete by pounding it with a wooden float.
SPENCER  MARTIN:
Usually some sort of agitation or vibration when you're laying concrete whether it be a great big slab or a little one like this.
RON HAZELTON:
Next we move bAck outside to mix a second batch of concrete.  We start with quick drying concrete but this time we add other ingredients.  First marble sand, followed by white Portland cement.   Then mineral pigments to give the countertop its color.  We blend these ingredients together, then Spencer adds one more.
SPENCER  MARTIN:
This is a black slag.
RON HAZELTON:
Slag.
SPENCER  MARTIN:
Yeah and it's - it's almost like glass.  It's very very shiny and it has a lot of different sizes of particles as well. 
RON HAZELTON:
So will this show in the final product?
[BOTH SPEAK AT ONCE]
SPENCER  MARTIN:
This will.
[BOTH SPEAK AT ONCE]
SPENCER  MARTIN:
Exactly.
  RON HAZELTON:
With the dry ingredients thoroughly blended, Spencer  adds water and I start mixing.
SPENCER  MARTIN:
Just don't splash yourself because it starts -it gets really slippery at this point.
RON HAZELTON:
This  colored cement will become the top surface of the countertop. For the exposed edges, Spencer will thin the mixture even further to help eliminate voids and air bubble.  After leveling off the finish coat, I lend a hand, pouring the thinned mixture around the edges.

A few strikes from a hammer along the side of the form knocks out any air bubbles along the edge.  Spencer uses a tool called a jitter bug to bring the fine particles or cream to the top. About an hour later, we check the concrete to see if it's hard enough to trowel.
SPENCER  MARTIN:
If you put your finger in, you'll leave a fingerprint but you won't pull up like a little dimple or cone. That means it's starting to harden up and we can start putting a trowel to it to smooth it out to the next layer.
RON HAZELTON:
Spencer trowels the concrete to smooth out and burnish the surface.  As the concrete continues to dry, he will repeat this process several more times over the course of the next few hours.  As for me, I'm going to leave the artist to do his art.

And come back tomorrow to see the finished project.  The next day, Spencer removes the form, revealing his masterpiece. Very nice. Michael, what do you think?
MICHAEL:
I love it.  I love seeing all the aggregate and the little pockmarks and it's a very organic look. And it's just so beautiful.  I just think it's fantastic.
RON HAZELTON:
Here's actually that black that slag - you put it earlier.
[BOTH SPEAK AT ONCE]
MICHAEL:
- exposes at the edges which I just love.
RON HAZELTON:
Michael, do me a favor, would you.  I'd love to see this when it's completely finished, when the sink's back in.  Would you snap off a picture and send it to me.
MICHAEL:
I'd love to.
RON HAZELTON:
All right, that would be great. Thanks guys both, both of you very much. This was very very interesting to me.

A few weeks later, I did receive that snapshot from Michael.  And I must say his concrete countertop is a perfect fit in his creative Santa Fe  home.