Diamond Blades, Cutting Concrete: Cutting with Lines , Grooves & Control Joints

Cutting lines, grooves and control joints with diamond blades is nothing new for concrete contractors, but enterprising craftsmen have been putting their creativity to the test by using the blades to produce decorative borders, graphic designs or V-shaped grooves that look like they were hand-tooled.

Tom Ralston, a third-generation concrete contractor from Santa Cruz, Calif., most often makes decorative saw cuts on interior floors in grid patterns (two-by-two-foot squares or three-by-three-foot diagonals) but says diamond blades can be used to cut any variety of designs.

"You can slice and dice a floor up like a boarding house pie," he says.

Diamond blades can be used to cut both green and cured concrete, using a variety of right-angle grinders, hand-held circular saws, Dremel tools or walk-behind saws. A variety of blades are available in the market, each serving its own purpose.

Ralston uses Norton/Clipper Corp.'s Slab Crab, a new saw with wide rubber wheels that allows him to cut perfectly straight lines; a Soff-Cut saw for structural cuts in green concrete; a four-inch grinder to make circular patterns; and a Dremel tool.

He likes to get out on the slab days after it's poured, lay out the design on his hands and knees, snap the lines using orange chalk — which doesn't stain the concrete — and make his cuts, often by hand. The saw cuts can act as small dams, making it easy to use different acid stains in the design without the colors bleeding into one another. For example, he created a unique design on a residential entryway using Italian marble in one section, black acid stain in another, antique amber with bits of real copper in another, and deep score joints filled with copper epoxy.