QUESTION: My 1950 Millard Sheets house, like many midcentury modern houses in Southern California, has Lithochrome concrete floors. Mine needs to be repaired and I'm wondering if you can recommend how I can find someone who does this sort of work.
ANSWER: Even before stained concrete became popular in midcentury modern homes, they were widely used in local Art Deco and Art Nouveau houses. It was so popular, in fact, that the L.M. Scofield Co., which created the Lithochrome products to color concrete, moved its offices from Illinois to California.
Scofield, which has been manufacturing Lithochrome concrete stains since before 1920, makes two types of Lithochrome products to color concrete: Chemstain Classic, a stain that is applied after concrete has been poured and dried, and Color Hardener, a colored powder that is dusted onto the concrete while it is still wet.
The acid stain, which comes in eight colors, is somewhat transparent, allowing the variations in the concrete to shine through, while the Color Hardener produces something more opaque.
According to the company, its Chemstain product is generally used on residential projects and, if applied correctly, the color should remain stable indefinitely. But if the product was not adequately neutralized after application, the color may eventually become unstuck and peel off.
If the stain seems to be scraping off due to wear, then you probably have a sealing problem. A stained concrete floor should always be sealed with a product compatible with the stain and protected with a wax made specifically for concrete floors. If an incompatible polyurethane sealer is used, for example, it may actually pull off the top layer of your concrete.
If either of these scenarios describes your problem, you will need to remove the stained surface through sandblasting or diamond grinding to get down to the raw concrete and start over. Make sure to thoroughly remove sealers or spills before applying the stain. Otherwise, it will not "take."
Crumbling, cracking or disintegrating concrete points to poor concrete strength, for which there is no good remedy. Here in Southern California, earthquakes can also cause cracks in concrete. Since these flaws are very difficult to erase, you might embrace them instead. Sherry Boyd, a director of marketing and sales at Scofield, suggests turning them into a feature by adding dark Chemstain or acrylic paints into the crack to accentuate it.
"Some people," she says, "even create added faux cracks to make the floor look older."
To find someone who can repair Lithochrome-stained concrete, consult websites such as www.concretenetwork.com. Scofield, at (800) 800-9900, can also provide names of local contractors. Interview the contractor, examine at least three of his or her projects, inspect references, and ask for a "job site mock-up," a reactivity test that should be conducted inside a closet, if it's an indoor project, or in another hidden area. Make sure to get specifics about the colors and products the contractor will use, including the name of the stain and the sealer, and, of course, a written price quote.
-- Christy Hobart