What to do about white painted floors starting to yellow

Jeanne Huber

THE WASHINGTON POST- Several years ago, we had the wooden floors at our vacation home professionally painted white. The contractor used an industrial-grade paint for use on factory floors and/or high-traffic wooden floors. I believe it may have been latex enamel and not an oil-based paint, as I don’t recall a chemical smell. We didn’t lay carpets on it for nearly a month to allow the paint to set. We do have yellowing underneath the area rugs now, which I believe is due to a lack of UV light. The finish has held up remarkably well, but I am having difficulty getting the floors really clean. Can you suggest a product or technique?

A: Your floors could indeed be coated with latex paint, which needs around 30 days before the resin bonds that create a tough film have fully formed. Latex floor paint often contains urethane, for added  scuff resistance.

Or the paint could be an alkyd-modified latex paint, which performs like oil paint but lacks much of the solvent smell. Alkyd paints are most susceptible to yellowing where light doesn’t reach, but yellowing can also occur with white paint made in any formula.

Regardless of the type, the paint on your floor should stand up to gentle household cleaners.

But, especially if it was a latex product, it’s important to avoid vinegar, ammonia and bleach, as well as abrasives, said Director of Research and Development Jason Hall at Rust-Oleum. (Mixing ammonia and bleach would be especially dangerous, as the mixture releases toxic chloramine gas.)

It is recommended to do spot-cleaning with water
Another good way to keep the floor from yellowing is to paint it to another colour

A customer-service representative for Sherwin-Williams, who would give only his first name, Joe, also advised against using ammonia, and he added another cleaner to avoid, alcohol-based cleaner.

You probably already know this, but your main cleaning routine should be going over the floor frequently with a micro-fibre dust mop or a vacuum with a tool suited to hard surfaces, not a rug beater. The more the floor stays free of grit, the longer the paint will look good.

For spills, muddy footprints or other grime that dust-mopping or vacuuming doesn’t remove, Hall, in an e-mail, recommended spot-cleaning. “The safest products to use are mild, general purpose cleaners,” he said.

Product information specialist Ali Forouzandeh at Benjamin Moore, and Tom Monahan, who works in sales for General Finishes, offered similar advice.

They recommended spot-cleaning with water. If that’s not enough, they suggested adding a little mild hand dishwashing detergent. Whether you’re using warm water, which cuts through grime better than cold water, or water plus a little dish soap, wet a rag, wring it out well and wipe off the crud. Think “wipe” rather than “mop”, because you want to avoid creating puddles.

Have a clean cloth ready and immediately wipe the area dry. If you’re using soap in the solution, take the time to rinse away the residue by wiping the area with a cloth moistened with warm water before you dry that section.

Never resort to steam-mopping. “The moisture and heat can warp and damage floorboards,” Hall said.

You can find numerous recipes online for cleaners for painted floors. Use caution, though.

Some recommend adding vinegar, washing soda or Borax, which might help cut through grease and remove stubborn grime when used in very small amounts (such as a couple of teaspoons per gallon of water). But these three ingredients are also key components in various recipes for homemade paint strippers, so use them only as a last resort and in a very diluted solution.

Rust-Oleum makes a two-part floor finish, Home Interior Floor Coating System. The base product is formulated to stick even to surfaces that normally wouldn’t grip to paint, such as vinyl and tile. You don’t need that functionality, because regular floor paint clearly stuck well.

But you can adapt the underlying philosophy to your floors: Once your paint is clean, consider applying a clear topcoat to protect the paint.

It’s possible to touch up areas you missed or add a fresh coat to areas you walk over most frequently. Be sure to spot-test first to make sure that the topcoat adheres and that it doesn’t create unintended effects, such as widespread yellowing.

General Finishes has online advice that warns against applying topcoats to white paint in general (not specifically to white floor paint), which you can read on the company’s website, generalfinishes.com, by typing “yellowing” into the search box. Monahan said a floor-refinisher-type product would be less likely to lead to yellowing than top-coating with a stand-alone clear finish, such as polyurethane, which he would not recommend using. Asked if there is a good way to keep a white floor clean, he laughed and said, “Paint it a different colour.”