QI intended to paint my garage floor until I was told that the paint would just chip and look bad quickly. What is your opinion?

-- Viveca

AConcrete garage floors can be painted successfully, but you must choose the correct paint and the concrete must be prepared carefully. In addition to the usual problems of painting concrete, garage floors have a special problem called hot-tire pickup. Tires contain compounds that can cause ordinary paints to peel, so many paint manufacturers have come up with special paints to deal with the problem.

You can find garage-floor paints at most home centers and paint stores. These paints are sold under many brand names including UGL Drylok, Sears Weatherbeater, Behr and Rust-Oleum. The paints are available in both epoxy and water-based formulas.

In general, garage-floor paints should be applied only to bare concrete. Any other paint or coatings should be removed. You should carefully read the directions on the paint container for special instructions and cautions.

Preparatory steps usually include sweeping the floor thoroughly, then vacuuming up dust. This is followed by scrubbing with a heavy-duty cleaner and degreaser, normally sold by the same stores that sell the paint. Tough stains might require several applications of cleaner. The floor should then be rinsed with clear water.

If the concrete is smooth or slick, it should be etched to give a better surface to hold the paint. A suitable surface should feel like fine sandpaper. Etching requires an acid solution that is sold by most paint stores.

Finally, apply the paint with a roller or pad. Two coats might be needed for adequate protection. And be sure to let the paint dry for the period specified on the container before parking cars on it.

I have trouble keeping my white ceramic tiles and grout clean, especially the grout. I applied bleach to the grout with a toothbrush, but it didn't work. Can you help? -- D. Lee

Many home centers and ceramic-tile dealers sell special tile-and-grout cleaners that usually do a good job. In many cases, regular household cleaners will also work. For example, I've had good reports about Simple Green as a tile and grout cleaner. You should not use abrasive cleaners, however, or the tile surface might be scratched.

A power scrubber such as the ScumBuster by Black & Decker (www.blackanddecker.com) can speed up and ease the job of cleaning tiles, bathtubs and many other surfaces. A power scrubber costs about $40, but is worth it if you are having cleaning problems.

Grout, especially white grout, is sometimes difficult to clean. If cleaners fail, another option is to stain the grout to a fresh white color or to another color that won't show dirt so easily. A combination grout stain and sealer is available from Super-Tek (www.super-tek.com) in white and a number of other colors. A pint, with applicator, is about $28.

Grout whitener (item 132365, four-ounce bottle, about $10) is also available from Improvements (www.improvementscatalog.com). Applying a sealer (also available from Improvements), will help keep the grout from getting dirty again.

I have also heard of people using white shoe polish on dirty grout.

My basement has a channel cut into the floor around the inside walls. The channel leads to a sump pump. Along the bottom of the wall is a space that has been filled with caulking. I've been told that this space should be left open so water can flow into the channel and to the sump pump. Is that correct? I don't know who installed the caulking. -- F. Allen

When drains of this type are installed in basements, holes about one inch in diameter are often drilled at intervals in the bottom of concrete-block walls. The holes allow water that gets inside the hollow concrete blocks to drain into the floor channels. It is possible that the "space" you describe is for this purpose, or it could simply be a crack that someone patched or tried to patch.

Your best bet is to have the drainage setup examined by a basement-water contractor. You might be worrying needlessly about something that is best left alone.

Questions and comments should be sent to Gene Austin, 1730 Blue Bell Pike, Blue Bell, Pa. 19422. Send e-mail to doit861@aol.com. Questions cannot be answered personally.