When does a GFRC concrete countertop look just like a cast in place concrete countertop?

I’ve heard people say that they don’t like GFRC because it looks too uniform, like plastic solid surface. Nonsense! GFRC can have any look any other form of concrete can. It is concrete, after all.

Here’s a great example. In summer 2011, I spent 3 months in the Cayman Islands helping my student Terry. We did a gazebo bartop using a cast in place technique and a mix delivered in a truck from the local batch plant.

Forming for the cast in place gazebo

Mix being delivered from batch plant

The finished look

We also did round and rectangular tables for a restaurant, and the owner wanted exactly the same look as the gazebo, plus some amber glass. But, the tables couldn’t be cast in place, and they couldn’t be too heavy.

No problem! With GFRC, I was able to create a face coat (like a mist coat, but with aggregate in it and obviously not sprayed) that exactly duplicated the look of the cast in place mix. Then I just applied a backer coat to that. The result: Just the right look and a happy client. GFRC made it possible.

Lots of buckets! This is the "batch plant" for GFRC.

The round tables, showing backer coat

The finished look

The oft-neglected step between templating and forming a concrete countertop

You know that templating and then forming are basic steps in concrete countertop making. But have you thought about the very important, but often neglected, step of slab layout? Slab layout should be carefully considered, first on a practical level and then on an aesthetic level.

The first step in slab layout is to determine the maximum length of slab that you can get into the house or space. Note during templating whether there is a tight corner you’ll have to carry the slabs around, or a narrow staircase you’ll need to climb. Although you may have the technical ability to make 20-foot long slabs (at least from GFRC), if you can’t physically get the slabs into the house, it doesn’t do you any good. (We’re talking precast here, of course. You could go the cast in place route depending on the look desired and the site conditions.)

Let’s say you’ve determined that the maximum length of slab for a kitchen countertop you’ve templated is 8 feet. At your shop, lay out all the templates on casting tables, right side up, as close as possible to the actual layout of the kitchen.

You will usually need a seam at the kitchen sink. Kitchen sinks tend to be placed in long, straight runs of countertops, which may exceed your maximum slab length. Usually the easiest way to seam a kitchen sink is to make one short seam in the center of the sink, lined up with the cabinet seam.

Sink with seam in center, front and back

Try to keep adjacent slab sections similar in size, rather than having one long piece abutting a very short piece. This looks odd and unbalanced.

If a slab must be “L” shaped in order to turn a corner without excess seams, the longest practical length for the shorter leg of the “L” is usually about 5 feet (measured on the outside of the L).

Other than these general rules of thumb, most of slab layout is aesthetics. Pay careful attention to the cabinet seams (defined by the center of cabinet doors, or the line between two cabinets). Nothing looks worse than a countertop seam 1″ off from a cabinet seam, or worse, a few millimeters.

Poorly placed seam - a few millimeters too far to the right

Also think about how the client will view the countertops in the room. Is one section visible from the main door into the kitchen, and usually spotlighted in a ray of sun? Then maybe it’s worth a little extra effort to avoid a seam right in the middle of that section, since the client will see it every time she walks into the room.

Once you’ve determined where you think the seams should go, draw the seams on a kitchen plan and have the client sign her consent. That way there will be no misunderstandings or disappointments later. Many clients get extremely emotional about every little detail of their kitchens. A decision that seemed like no big deal to you can seem like the end of the world (and the end of your profits) to a client.

Once the seam layout is finalized, draw the seams on the templates and cut them with kerfless shears. These cut templates will be what you form around. And since you’ve taken the time to create a carefully considered seam layout, you know your forms will create the perfectly sized and fitted countertops for your client. And a perfect product means a happy client!

How to template a curved wall for a concrete countertop

If you’ve been in construction for more than a day, you know that walls are never straight and corners are never square. Sometimes walls are downright curvy. How can you deal with this when you’re using straight template stock? You want your concrete countertop to fit properly!

One method would be to cut into the template stock to fit the curvature of the wall. However, this requires cutting a little, fitting to the wall, shaving off a little more, and repeating many times.

A much simpler way is to build up the template edges to fit the wall. Simply run the template stock straight along the wall, which will expose the gaps where the wall curves in. Then attach small “fingers” of template stock to fit the curves. The more curved the wall, the thinner the fingers should be in order to accurately record the curvature. 

In the photo below, the corner is far from 90 degrees. The wall is straight up to about 2 feet from the corner, then curves out almost an inch. Since this countertop was to have no backsplash, the countertop had to fit flush to the wall. Even if this countertop had a backsplash, the extreme curvature of the wall would have required making the countertop slab at least a little curved.

Notice in the photo that the edge is marked “No B.S. Fit to wall.” (No backsplash.) There are 3 fingers starting where the wall curvature starts. Attaching these fingers to the template took only a few seconds.

This simple technique will result in more accurate templates and save a lot of time.

Recent cool concrete countertop projects by students

Recently I’ve had several students send me photos of cool concrete countertop, bartop or sink projects they’ve been working on. Check these out!

Brent Gwynn of Pro Builders Construction in Rices Landing, PA


Brent attended the Ultimate Concrete Countertop Training class in March 2012, and just a few short weeks later, he was installing this concrete retail counter for a local beer store. Congrats Brent! I hope you get free beer as part of the deal. (Nice shop too! Very impressive organization.)

Ajaay Srinivaas of Nuance Studio in Bangalore, India


I visited Bangalore, India to train Ajaay in late March/early April 2012. Since then, he’s been flooded with orders for concrete sinks, or “washbasins” as he likes to call them. I’m so excited about the innovative designs he’s come up with, and the fine detail of the craftsmanship. Great job Ajaay! (See my article about the India trip here.)

Shorlette Francis of Creative Collections in Nassau, Bahamas


Shorlette attended precast and GFRC class in 2008 and has been plugging away ever since. As you can see, she has horrible working conditions. 😉 This concrete bartop incorporated classic Caribbean elements of shells and beach glass, and it looks fantastic. Shorlette, I will have to come down there and celebrate with you!

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