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Vertical Overlays with
Decorative Concrete
Going Vertical. Experts share some straight-up advice on overlays
by David Thompson
Stucco may have once been en vogue for exteriors, but stenciling, done in a variety of brick and stone patterns, has become a popular application these days. A natural grout look can be achieved by leaving the first coat uncolored and applying a tinted layer over it. Adhesive-backed stencils work particularly well on vertical surfaces.
Stamping has grown in popularity in recent years with the advent of new products designed specifically for verticals and ranging in depth from 1/4 inch up to four inches. A variety of stone, block and brick effects can be achieved with off-the-shelf stamping tools, but sometimes stamps can be improvised.
When David Long needs wood textures in his theme construction, for instance, he turns to lumber. “We'll cut it to the dimensions we need, sandblast the face to raise the grain, and use the actual lumber for a stamp,” he says.
Hand tooling, or carving, is another option with some vertical overlay materials. Sharp-edged tools can be used to create scores, designs and even relief sculpture while the coating is still in its plastic stage. “I've seen everything done from a coat of arms to a family's actual features,” says Bill Tott, technical director of ArcusStone, a California-based overlay manufacturer. “One of our artists carved a whole family — four faces — right on the pillars of a fireplace.”
Cementitious overlays can also be applied to extruded polystyrene forms cut to replicate architectural stone details, such as arches, columns, windows and door surrounds. Not only do cementitiously-coated forms represent a cost-effective means of achieving elegant effects, they also weigh a heck of a lot less than the actual articles. “You can literally stick some of these things on with adhesive instead of mechanical anchors and ties,” Tott says.
The same coloring materials used on horizontal overlays can also be used vertically, such as integral colors, acid stains or even broadcast hardeners. However, some adjustment in application technique may be required, especially with liquids. When Rick Smith sprays acid stain onto vertical overlays, for instance, he slightly increases his compressor's psi, stands a little farther from the surface and applies the solution in a finer mist. He follows up by blotting the surface with a crumpled lambs-wool chamois to take out any runs, then hits wet spots hiding in cracks and crevices with a dry terrycloth. Or sometimes he just throws dry sawdust up on freshly-stained walls to soak up excess moisture, then washes it off later.
To protect new overlays from abuse of the elements, sealing is crucial. All the principles of sealing floors apply to sealing walls, though fewer coats ordinarily suffice where foot traffic's not a concern. Solvent-based acrylic sealers with matte finishes are a popular choice, especially for interior walls. Glossy finishes are sometimes used for exteriors, where they matte down with time.
In commercial areas such as restaurants, where contact between vertical surfaces and greasy-handed employees can be expected, urethane- or epoxy-based sealers may be warranted. “If there's ever a concern for a lot of wear and tear, upgrade,” says Wes Vollmer of Alternative Finishes in San Antonio, Texas. Vollmer adds that when he bids on such jobs, he points out to the architects that he's included the higher-cost sealers, which can substantially raise material costs.
For a different look, Rick Smith occasionally uses beeswax or even automobile wax as a sealer, which gives a satiny finish that you can't get with conventional sealers, he says. “It gives you this really bitchin' Old-World look.”
Interior vertical overlays should be resealed every three to five years, while exteriors should be resealed every two or three years.
Despite the similarities between vertical and horizontal overlays, contractors well-versed in floors shouldn't jump straight into walls without doing some mock-ups first. “Go out in the garage and get an old piece of sheetrock or plywood and mimic a wall,” says Vollmer, who has mastered a variety of vertical applications, including a faux Venetian plaster. “I always tell guys, practice makes perfect.”
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