This cast-in-place carved concrete fireplace surround was easier to craft in-place compared to constructing a curved mold for precast work and the results are stunning.
Ake Grunditz This cast-in-place carved concrete fireplace surround was easier to craft in-place compared to constructing a curved mold for precast work and the results are stunning.

Overlay cement for vertical applications is used for troweled finishes, stamped and textured masonry unit patterning, and hand-carved decorative applications. Doing architectural and decorative carved work provides stunning results in the hands of a skilled artist. Ake Grunditz, owner of Fine Design, Alameda, Calif., is one of those people.

He uses vertical overlay cement trowel applications as thick as 3 inches to carve architectural features onto fireplace surrounds, kitchen vent hoods, entry features for homes (such as arches and columns), window and door surrounds, and wine cellars. He even worked on an Egyptian exhibit for a university library.

Working from stencils

Grunditz almost always uses stencils in his process, which he makes himself. “I use some of them more than once but most of what I do involves pattern creation with a client for a single use,” he says. “I use fairly heavy paper or brown wrapping paper. The paper must be able to resist a certain amount of moisture.” Next he cuts slits in the paper that follow his pattern. Then he places the paper against the fresh overlay mix and sprays black paint over the stencil, coloring the concrete where he cut the slits.

Overlay requirements

Grunditz uses preblended polymer cement products for his work. The ones he favors most include blends of both large and small limestone aggregates. His first task is to sift out the larger aggregates because they interfere with fine carving work. He also mixes liquid polymer into the mix water in equal proportions, making the mix more “gooey,” but easier to carve. Color pigments can be added depending on what the client wants. His mix is fairly stiff so that it easily trowels onto wall surfaces. He notes that he has 10 to 15 minutes to apply a batch to a wall surface before it begins to stiffen.

Grunditz develops his own patterns for each of his projects. The patterns have slits cut into them to allow black spray paint to mark the pattern on the fresh concrete.
Ake Grunditz Grunditz develops his own patterns for each of his projects. The patterns have slits cut into them to allow black spray paint to mark the pattern on the fresh concrete.

Work by other contractors usually precedes Grunditz's so they frequently do the surface preparation that he needs. He starts by applying a wet version of the same mix with a brush to get a good bond, then within 5 minutes, begins troweling the mix he will carve. Once the material is in place, he typically has six to eight hours of carving time if temperatures are in the 70º F range. He starts carving immediately after the overlay cement is troweled on.

Carving

Grunditz is shown cutting out the basic shape of his pattern. Next, he will refine his work by cutting finished curving shapes into the outlined forms.
Ake Grunditz Grunditz is shown cutting out the basic shape of his pattern. Next, he will refine his work by cutting finished curving shapes into the outlined forms.

Grunditz says that he prefers using carving tools intended for ceramic sculpturing, mostly scrapers and knives readily available in art stores. He first carves out the basic pattern defined by his paint marks and then goes back to refine the shapes. To keep one work area from getting harder or dryer than another, Grunditz sets up wind screens to protect his work from surface drying and shades to keep the sun from heating up some areas more than others. When the carving process is complete, clients often ask him to apply color washes to provide an additional 3-D effect. He also applies penetrating sealers for a finishing touch.

Starting his company in 1991, Grunditz says his work is still fun. He likes working with his wife Leslie, also an artist, who frequently works with him on jobs, making the working experience even more enjoyable.