Q: The oak flooring in my post-and-beam house was installed in 1988 and has not been properly cleaned in at least 15 years. Otherwise, though, it is in great condition. The flooring consists of ­3½-inch, tongue-and-groove solid oak planks stained golden oak and finished with a water-based sealer. I have washed some areas using mild soap and water, but I am hesitant to continue without some direction. How should I proceed? Do I follow the same advice on cleaning the posts and beams throughout the house?

Trappe, Md.

A: Because your floors have stayed in good condition for 15 years, it’s likely the wood was coated with an actual finish, probably an acrylic, and not just a sealer. When the finish is intact, that’s what you clean: the plastic coating, not the underlying wood. Sometimes the finish wears through, so dirt collects in the wood itself. Then, no matter how much you scrub, or what product you use, the floors never really look clean. The only option in that case is to remove what remains of the finish, sand down to uniformly bare, clean wood and start over.

The pictures you sent show dirt along the edges of the floors, rather than farther out. That’s a good sign, because if the finish were worn away, it would happen first in the main walkways. So, it appears you just need to clean.

You can use a hardwood floor cleaner, such as Bona Hardwood Floor Cleaner or Bruce Hardwood and Laminate Floor Cleaner. Home Depot carries both products in 32-ounce spray bottles — $7.97 for Bona’s product and $4.48 for Bruce’s. The spray products deliver a mist that you can wipe away with a mop while you are standing up.

But if you are able to get on your hands and knees, plain water, or water with a little clear hand-dishwashing detergent, also works. Especially because it’s been a long time since the flooring was cleaned thoroughly, working this way will enable you to see what is going on and help you match the amount of cleaning in various areas to where the most grime is found.

Use warm water and have a supply of clean cotton rags. Dampen one, wring it out well and fold it into a manageable pad. Wipe an area, then immediately go over it with a dry, clean cloth, also folded into a pad. Using folded rags allows you to refold them to expose clean areas, saving you from having to get up and down so often.

If the cloth you are using to dry the floors stays clean, the finish on that section is clean. If the drying cloth picks up dirt, refold the damp rag and go over that area again. If a section still isn’t clean, or if it seems oily or tacky, switch to warm, slightly soapy water to help dissolve grime. You especially might need this approach near the kitchen stove. Wipe away any soapy residue with a second cloth that is moistened only with water. Stick to the same process: Use a well-wrung-out cloth and dry the section of flooring with a clean cloth.

Never use floor cleaners designed for vinyl or tile on wood floors. Be cautious about adding vinegar to your wash water. If you poke around on the Web, you will find lots of advice telling you this is a good way to cut through stubborn grime. That’s true — but it’s also true that vinegar is acidic, so you risk etching the finish. Test the effect first in an out-of-the-way section of the flooring, perhaps in a closet.

If the floors look dull even after cleaning, it is probably time to coat with another layer of finish. You or a hardwood floor refinisher will need to scuff up the surface slightly, then apply new finish. This is called “screen and recoat” or sometimes “buff and recoat,” because the prep work is done with a floor-buffing machine fitted with a mesh pad encrusted with fine abrasives. The screen scratches up the old finish just enough so that a new coat sticks; it is far less aggressive than using sandpaper, which will wear through the finish. Recoating floors before the finish wears through saves money and keeps you from having to sand down to bare, clean wood, which inevitably wears away some of the wood.

As for cleaning the posts and beams, you can use the same method for wood that is within reach, but higher up you’ll need to modify this procedure. To extend your reach without a ladder, use a tool with a telescoping handle. Katahdin Cedar Log Homes, a log-home manufacturing company in Maine (katahdincedarloghomes.com), recommends the Unger 20-foot Connect and Clean Telescopic Pole, which weighs just over ­
3½ pounds because it’s made of aluminum ($34.97 at Home Depot). Katahdin recommends outfitting the pole with the Unger Microfiber Ceiling Fan Duster ($15.11 at Home Depot). Or you can use a telescoping paint roller with a lamb’s wool cover.

Cleaning with just a telescoping handle doesn’t give you much leverage, and it’s tiring. You may want to invest in a telescoping ladder, which will allow you to work closer to the wood. Katahdin recommends a 14-foot Telesteps Telescoping Ladder, which retracts to three feet tall for easy storage. The design also allows you to work safely on stairs. It’s $379.10 at Home Depot, but as a special-order item at many stores.

If dusting doesn’t get the posts and beams as clean as you want, try washing the wood with warm water or warm, soapy water. But test a small area first, because the structural wood might not have the same finish as the flooring. Make sure the water or cleaning solution doesn’t change the color of the wood. In a kitchen, you might need to add vinegar to help cut through grease. If you’re using a wool or microfiber cleaning head, wash it frequently, and roll out excess water on a towel so that you don’t drip water all over the room. The structural wood might be rougher than the flooring. Wipe in the direction of the grain.

Or, far easier, hire a professional cleaning company equipped to clean vaulted ceilings.

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