01:00 AM EST on Sunday, November 6, 2005

I am buying my grandmother's 1952 house for a good price, and I want to spend money to fix it up, but not too much. The three bedrooms have hardwood floors that I think my grandparents waxed. We have been ripping up carpets in these rooms; they have been replaced many times, and the floors are in very good shape, believe it or not.

Could I strip the old buildup of wax with ammonia and then polyurethane it? I have seen about "screening" a floor; it looks like sanding to me. I want to do the work myself but don't want to ruin the floors.

What should I do to save as much cash as possible?

I believe you when you say the floors are in very good shape, so why bother to redo them when they don't need it? Your comment about all the times carpeting was replaced over the years was interesting, indicating to me that some wall-to-wall carpeting is not worth the material it is made of. That's an opinion. So you can put wool Oriental area rugs down, or even wool broadloom, not any fancy ersatz pile. They can outlast the floors.

Another way: Strip the wax with a wax stripper, and apply a good floor wax, buffing it with a power buffer. It is a lovely finish (like the one you have now).

You will want area rugs on this new finish. No wood floor will stand up to furniture and scuffs from shoes.

Of grades and grain

What is it meant by the term "grade of abrasive paper" and what is it meant by the term "raising the grain," and why is it carried out?

The "grade" (or grit) of abrasive paper (sandpaper) refers to the size of the abrasive particles in the sandpaper. Given the same number of passes and the same amount of pressure, paper with larger particles sands deeper (and rougher) than paper containing smaller particles.

A lower number indicates that the grade of the paper is used for rough sanding where a high number indicates the sandpaper is meant for finish sanding. Generally speaking, 30- and 60-grit papers are used for rough sanding, 100- to 150-grit sandpaper is for medium sanding and 220-grit sandpaper is used for finish sanding.

Of course, this changes with the type of wood and whether the sanding is done by hand or with a machine.

Sanding a soft wood with rough sandpaper could possibly tear the wood fibers (the grain). Sanding perpendicular to the wood fibers could also tear the wood fibers. When the fibers tear, they raise from the surface.

The best way to determine what grit to use is to test-sand. Keep in mind that rough grits of sandpaper leave deep scratches, so start with the finer grits (150 to 220) and slowly work up to the rougher grades.

"Raising the grain" is what painters must contend with after the first coat of paint is applied. At this point, and once the paint or varnish has dried, the first coat and the raised surface must be smoothed. The second coat of finish usually will not raise the grain. This is because the wood is protected from absorbing moisture by the previous coat.

Dehumidifier too strong

For most of last summer, my dehumidifier never stopped running in my basement, pulling gallons of water out of the air, but it did not seem to do much good in drying out the basement. Then I discovered water under the carpeting, and a fair amount of water on the floor around the toilet. I called a plumber, who could find no leak. You suggested I ventilate the basement to allow water vapor to escape, but I could not do that on very humid days. What can I do to reduce moisture?

I think it is a matter of too much too long. The dehumidifier is quite large, and is not only pulling moisture (water vapor) out of the air, but is pulling water vapor that is under the slab, right through the concrete, faster than it normally would go through it. Then it condenses under the carpet and on the toilet, where it wets the floor. There are no leaks.

Your best bet is to ventilate by opening windows for cross-ventilation, but of course only on dry days. You can give the air a boost with an exhaust fan. Days and nights are generally dry in April, May, and June, and in September and October. July and August, when it seems to be humid all over the world, is the time to use the dehumidifier. There is less need to ventilate or dehumidify in cold weather, which the air carries less moisture.

Compiled from Associated Press and Boston Globe reports.