Old trick should revive wood floors

Q. In my six-year-old house, the hardwood floors are already in need of refinishing. They are badly worn, scratched, and a general mess. They were treated with several coats of a water-based polyurethane varnish. I know I have to have them sanded and refinished, but is there a coating that would stand up to wear and tear better than mine did in just six years?

JOHN ANDRIOLA, Greenland, N.H.

A. Sure is. It is called oil-based polyurethane varnish. Have the refinishers apply at least three coats of this stuff to your sanded floors. While oil-based varnish will stand up to wear and tear better than water-based varnish, it will still be vulnerable to scratching, so I suggest you put down area rugs to prevent this, and/or put rubber crutch cups on the legs of tables and chairs that are not on carpets.

It's funny. Progress is usually measured in fits and starts, one step forward and two back. How many times have we cruised along, fairly comfortable, with such old-fashioned things as, well, oil-based varnishes and polyurethanes. Then some young whippersnapper comes along and develops water-based polyurethane varnish. Admittedly, it is easy to clean up, is safer for the environment, and works beautifully on woodwork and furniture, but you need to put up to seven coats on a floor. Where is the progress in that? I am no Luddite, but sometimes old is not old-fashioned. I also am whistling in the dark, because eventually all oil-based materials will be banned. Whoopee.

Q. I had new ceramic tile installed, with a light-colored grout that has gotten dirtier and dirtier, and moldier and moldier. How can I clean it and how can I keep it clean?

PANICKED

A. Back in 1950, some deep-thinking designer came up with a brilliant idea. Let's make the grout white or pastel colored to match the decor, instead of ugly old dark gray floor grout. Won't it be lovely. And Mrs. Housewife said, "Ooh, that will be lovely." And so it came to pass, and the white and pastel grout looked beautiful for a week or so, then got dirtier and dirtier, and moldier and moldier. Mrs. Housewife despaired.

So, to clean the grout, scrub it with bleach, several times until it looks clean again. And, once clean, seal the grout with a tile sealer. This will make it water resistant and washable, therefore resistant to dirt and mold.

A permanent solution is to dig out all that dirty grout and put in a very dark grout; dark gray or black, if possible. It will not show dirt.

One more trick: Whenever you tile a floor or wall, use larger tiles to reduce the number of grout lines. And, make the grout lines just 1/16th inch; that is not too narrow. One-eighth is also OK. The narrower the grout line, the less it will show. The old-fashioned ways still work.

Q. When I had a swirled ceiling repaired, the workman did not swirl the plaster in the repaired section, leaving a smooth ceiling. Can I reswirl it myself?

GARY STASNY, St. Paul, Minn.

A. You can certainly try. If the swirls are in the plaster, you can apply a skim coat of joint compound and swirl it before it sets too hard, using a stiff whisk broom or other brush with distinct bristles. If the swirls are deep, you can try swirling with a notched trowel. If the swirls are in paint, you can apply a thick coat and swirl it with a whisk broom or brush.

That infernal internal hum
Remember Linda from Florida who had a continuous, high-pitched hum or high-frequency screech in her house that would not go away? She told her tale to the Handyman early in March. While the Handyman offered some solutions, he received several ideas from alert and thoughtful readers.

Wrote Norman of Haverhill: You did not ask Linda if she and her husband wore hearing aids. My father-in-law did and when he was in the presence of a rheostat, such as is a dimmer switch, he was plagued with a high-frequency noise. Some fluorescent lamps also caused this phenomenon for him.

Here is what Charles Small, an engineer friend of the Handyman, e-mailed: A large transformer with loose laminations - these are the stacked, soft iron frames that couple the magnetic field to the coils when a high current passes through the transformer. They would vibrate at a frequency of about 60 cycles per second.

Also, a gauss meter [which measures magnetic fields] would pick up the magnetic radiation. I made myself a little tester using earphones and a battery-operated amplifier for hearing assistance. In place of the microphone, I substituted one of those pickup coils that Radio Shack sells for connecting a tape recorder to the telephone near the receiver.

If, like me, one has "T" coils built into their hearing aids, one can pick up the hum from a power line when walking under a high-voltage transmission line.

Also, with the "T" coil in the hearing aid switched on in place of the hearing-aid microphone and your toaster turned on, one will hear the hum from the magnetic field surrounding the toaster element. If one then rotates the toaster, the volume will increase and decrease due to the change in coupling in the earth's magnetic field.

From George W. Adduci of Rockland: The hum in my house was caused by the clothesline connected to my attached garage. The clothesline was attached to a metal T-shaped pole by way of four pulleys - two on the pole and two on the house. The line was pulled as tight as possible. When the clothesline was empty, the wind would blow across the lines causing the vibration or humming sound in the house. Once I removed the connection to the garage, the sound was gone.

And from Polly Sullivan of Newton Centre: Several years ago I began to have a similar problem, i.e., a low-grade hum throughout the house. I inquired around and found that readers mentioned telephone poles and wires as causing problems. One night, I received a call from the police asking me what my emergency was about, because a 911 call registered on their board as coming from my number.

I informed them I didn't call 911; the police were left to wonder who was really calling 911.

Shortly after this incident, my telephone lines went dead and I called repair. When the repairman came to the house, I told him the problem. He checked out the lines, and reported back to me that he was putting me on a new line. The humming stopped. I suspected that many, many people shared the same line. Only recently I have begun to hear a slight humming sound once more. I will monitor it and if it continues or increases, I will call repair - again.

Q. I have black spots growing on my molding; it seems to be under countersunk nails and screws covered with putty. What are they and why are they appearing? And how can I get rid of them, permanently.

DAVE BROWN, Methuen

A. The black spots are mold, and you can get rid of them by treating with a bleach solution. Dab on the bleach; the spot should disappear in five seconds. If it doesn't, it is dirt, which takes a little longer to form on molding.

The black is occurring because those nail heads and screw heads are colder than the wood molding, even under the putty. Water vapor condenses on these cold spots and chances are mold will grow faster than dirt can gather. The cure is to reduce the amount of water vapor in the house, by ventilating, or in summer, with air conditioning.

Globe Handyman on Call Peter Hotton is also in the Styles Section on Thursdays. He is available 1-6 p.m. Tuesdays to answer questions on house repair. Call 617-929-2930. Hotton also chats online about house matters 2-3 p.m. Thursdays. To participate, go to Boston.com. Hotton's e-mail is photton@globe.com.