Troubleshooting
Concrete Countertops:

If you're new to making concrete countertops, you may have encountered any of a number of pesky problems. Even experienced concrete countertop artisans encounter a problem now and then, but they will also tell you that practice makes perfect.

The countertop experts have worked for many years to hone their techniques, which are now so second nature that basic challenges of the medium are no longer much of an issue. Thankfully, for the most part, these experts are willing to share insights into the process of creating concrete countertops.

Across the board, the experts point out that it is important to first look at the process as a whole, rather than individual steps, because all parts of the process are ultimately related. For example, the physical site of installation will dictate the size and shape of precast countertop sections if the sections need to be transported up several flights of narrow stairs and through narrow doorways; so, in essence, the end affects the beginning.

Here's a look at some of the more common issues related to concrete countertops, and tips from the experts for avoiding problems.

Molds and mix design
The majority of concrete countertop artisans I talked to do not cast in place, primarily because they have greater control in their own studios. Of course, by precasting the countertops, transportation and installation then become major parts of the equation. Nonetheless, whether you precast or cast in place, mold making and mix design are very important.

Many experienced concrete countertop makers use different mix designs for different projects. Steve Rosenblatt, marketing director at Sonoma Cast Stone Corp. in Petaluma, Calif., says, "We use one of our 23 batch mixes based upon the application of each project. This is far more scientific than the countertops we made four or five years ago, and vastly superior to the original tops we made 12 years ago."

Rosenblatt reports that mold-making and reinforcement are also much more involved than in years past. "We use stainless steel, rubber, fiberglass, melamine and mild steel for molds, depending upon application and the number of pieces to be cast."

In Burbank, Calif., David Cunningham, owner of David Jack Corp., advises thinking through the mold making. "If you're doing a thick slab, more than 3 inches, use stronger materials or use external bracing. Most people use melamine - we do - but if there's a chance of bowing I use a piece of angle iron."

Michael Karmody, principal of Stone Soup Concrete in Florence, Mass., points out that the most dangerous time in the making of concrete countertops is when you de-mold.