How-to Paint Fiber Cement
My Victorian-era home is painted with three shades of purple. I am planning to re-side the house with fiber cement, but I can't find any manufacturer that offers those same colors. What are my options? —Denise Danielle DeFelice, Wilton, N.H.
I took your question to Rich O'Neil, a painting contractor at Masterwork Painting & Restoration, who has appeared on Ask TOH TV episodes. Here's what he had to say.
"Have you checked out the colors offered by James Hardie? Their factory-applied, baked-on topcoats come with a 15-year warranty against fading, chipping, peeling, or cracking.
"If their color selection doesn't meet your needs, talk to someone at a lumberyard that stocks it. He may be able to point you to a local company that can apply a custom baked-on finish; fiber cement's weight and brittleness make long-distance shipping impractical. However, even if you do locate a prefinisher, it may not be cost-effective to order three different shades. One prefinisher told me that the minimum cost for each custom color would be about $980, with a minimum run of 500 square feet.
"It might be better to just paint the fiber cement after it's installed. Order unpainted fiber cement, which is primed at the factory, then cover it with a top-quality, 100 percent acrylic exterior paint using any colors you want. I recommend two coats, after the boards are gently cleaned with a pressure washer and allowed to dry for a few days. Don't wait too long before painting; the exposed primer breaks down after about six months.
"Also, make sure that every board end—at the corners and in each course—is covered with an elastomeric or acrylic-latex caulk. Without that protection, those ends are liable to let moisture in and deteriorate.
"Site-applied paint on fiber cement should hold up very well—much longer than painted wood—but it certainly won't have the longevity of a factory finish."
—This Old House Host Kevin O'Connor