: Have you done an article recently about which product is the best for cedar-deck sealing? I am amazed at how little the employees at the home-improvement centers (and even the paint stores) know about yellow cedar and which product is best. I have given up on using stains, as they do not last and the maintenance work each year is overwhelming.

Do you have any product recommendation on a clear sealer for a cedar deck? I have all the old finish removed and sanded - all ready to go, but just don't know what to use!

Answer: Whatever you buy and no matter what it says on the can, a deck-sealing job typically lasts only 18 months. If you want the coating to last even that long, you should clean the deck every 90 days during the peak outdoor season.

The problem with cedar is that the wood is so dense sealers have trouble completely penetrating it. I've heard good things about water-based epoxy sealers. I haven't had a chance to test them because I no longer have a cedar deck - or even a deck, for that matter - so I can't recommend any. Just look on the Internet, pick a couple, and try them.

My colleagues in the industry advise against power-washing a deck before sealing, no matter how dirty it is. One reports that every deck he has seen that has been power-washed has wood that looks "fuzzy." Instead, they recommend using oxygenated bleach - not chlorine bleach - to clean decks. Chlorine tends to corrode nails and other fasteners and can harm tender plants nearby.

Q: We own an 80-plus-year-old, three-story Colonial with a full bathroom on the third floor. We recently learned the cast-iron stack is leaking at some unknown point below the third-floor bath. The estimate to replace the stack below the third floor with cast iron is $16,500. Plastic would cost $11,500. That does not include repairing the plaster walls after the pipe is replaced.

My wife and I are in sticker shock. We did not anticipate it would cost that much to replace roughly 20 feet of vertical pipe.

A: That does seem high. I suggest you get other estimates, or at least see whether there are ways to pinpoint where the leak is and repair it. Some plumbers use video cameras to troubleshoot problems in soil lines through front yards from the house to the street. Perhaps you can find one who does that to locate the leak in the stack before you decide on your next course of action.

I've employed plumbers who thought PVC (plastic) pipe was garbage; others swear by it. I had a PVC soil stack installed when our master bath was done several years ago. It seems to work fine. Learn everything you can and then decide.

Q: Can you suggest a better way of cleaning baseboard heaters (gas with forced hot water)? We used a small, indoor portable vacuum cleaner before the start of the heating season. Apparently that cleaning was not enough. My doctor says my worsening asthma is related to the heating system (dust mites are the culprit). This house is about 30 years old, we have lived here 18 years (no problems with the baseboards until this year).

A: Weekly vacuuming can help to further remove dust mites. People with allergies should use a vacuum with a HEPA (high-efficiency particulate) filter or a double bag, because standard or water-filtered vacuum cleaners stir dust up into the air. Allergic individuals also should wear dust masks while vacuuming.

One other thing to consider: Your house may be too humid in the winter, and dust mites thrive in high humidity. To reduce dust mites, it's important to keep humidity below 50 percent throughout the home by using a dehumidifier.