Q. I live in a four-story condo building with 64 residents. It is my understanding that if we do not upgrade our older furnaces to 80 percent AFUE (annual fuel utilization efficiency) by May 1, we will be required to install 90 percent AFUE furnaces after that.
The main problem is that our furnaces are installed in tight closets in the middle of our units. All four floors share a 10-inch-diameter flue up through the roof, with a total of 16 flue stacks penetrating the roof for all 64 residents.
The problem we face is venting the furnaces. Our choice is vertically up through the roof or horizontally through the outer wall. To go horizontally, we would have to run through a bedroom before we exit into a brick wall. Vertically, we would have to core drill the second, third and fourth floors and then the roof. This option is the least desirable, as those furnaces would have to be removed before drilling.
My question is, what other options do we have? Our six buildings were built in the early 1970s.
A. The Department of Energy has mandated that all replacement non-weatherized (indoor) gas furnaces installed after May 1, 2013, will need to be AFUE 90 percent in northern regions and 80 percent elsewhere. Oil-fired furnaces will have to be AFUE 83 percent everywhere.
Existing furnaces are grandfathered and do not need to be replaced if they are functioning properly, so I assume you need to have yours replaced for some technical reason. I don't understand why you are concerned about being made to go from 80 percent AFUE to 90 percent AFUE condensing furnaces. Why not go ahead and do it to improve the efficiency as much as you can? You'll benefit in the long run, and the difference in cost between the two furnaces is not that great.
The next question is venting. Under current code, several furnaces cannot be vented into one flue, so the best solution seems to be to vent horizontally. Running the vents through a bedroom at the joint of the wall and the ceiling is done in some college dorms, and probably in other situations. The vents will be either one pipe within a pipe to provide fresh makeup air or two separate pipes, depending on the manufacturer of the furnace. They can be boxed in to conceal them.
But there are code restrictions that will have to be observed. The exhaust pipe needs to be several feet from any openable windows on each side and above; the distance depends on the local requirements.
Q. I wrote you before on this subject, but this time I need advice on how to repair the problem. I get a small amount of water in my basement just when it rains hard and the wind blows it against the front of my house. When it rains hard and there is no wind, nothing comes in. The ground slopes away from my house, but water still comes in when the wind blows it against the house.
In the spring, I want to get it repaired by a professional company. People are telling me they will just come in and repair it in the basement, but I want it repaired from the outside so I can refinish my basement.
What questions should I be asking, and what type of material will the professionals use on the outside to waterproof the walls?
A. Any repairs suggested by waterproofing contractors will be costly and should not be needed for such a small problem.
From the conditions you describe, it sounds as if rain hitting the front wall of the house either runs down along the foundation wall and is not absorbed by the soil or follows the wall and leaks inside at the joint with the foundation. If the water is coming in at the joint of the basement floor and wall, it's the former, but if it is running down the inside of the basement wall, it's the latter.
In the latter case, caulking the joint of the mudsill and the foundation and the joint of the mudsill and band joist should stop this infiltration. Use polyurethane caulking compound under the Sika brand, available in masonry supply houses and in the masonry aisle of the Home Depot.
If the former, remove a band of soil against the front wall about 6 inches deep and a foot wide with a slight downward slope. Clean the foundation wall thoroughly and lay a strip of 6-mil black plastic in the trench and going up the wall a couple of inches. Apply a 6-inch-wide self-adhering tape to the plastic and the foundation wall and roll it tightly against the wall to ensure complete adhesion. You should be able to find the tape in building supply houses. Backfill and plant grass or a thick ground cover, such as pachysandra. This should work and cost you a lot less.
Unless you can do the work yourself, hire a contractor or knowledgeable handyperson.
Q. I have a white Corian counter approximately 21 years old. I wonder if there is a home remedy to restore the luster to the surface? There aren't any gouges as such, but the surface is dull and has watermarks on it. Also, would this work for the same type of surface but a gray speckled color?
A. Corian is a solid product throughout; it is impervious to penetrating stains. Stains that develop are only on the surface, and they are there because the surface was not wiped clean before the spill or water dried, leaving a film that will make it look dull. Corian also can become dull from polishes erroneously applied on it to clean it.
Corian countertops are usually delivered with a matte finish, and they should be cleaned with abrasive cleaners such as Comet and a Scotch-Brite pad. Wet the top and make a slurry with the Comet; it cannot hurt the Corian. Newspaper print and some stains also can be removed easily with a Clorox bleach pen or Clorox wipes.
If your countertop was delivered with a semigloss or high-gloss finish, the cleaning treatment is different. Clean the Corian with soapy water or an ammonia-based cleaner (not window cleaner, as it will leave a residue).
Commercial countertop cleaners are also available. But in all cases, be sure to wipe the countertop thoroughly dry after each cleaning.
If the Comet treatment is not as effective as you would like because of years of improper cleaning, an alternative is to sand the Corian by hand with 150- to 180-grit paper. You can use an electric sander with a vacuum cleaner attachment, or, if not available, wet the top to keep the fine sanding dust from spreading throughout the house. The resulting dust is similar to that from sanding drywall compound.
Q. We have a ranch house built in 1965 with an oil-fired hot-air furnace and partially finished basement. The furnace was replaced in 1999. Recently we had a fireplace-insert pellet stove installed that heats the living area upstairs and keeps the heat from running as there is only one thermostat in the living room, opposite the fireplace. The thermostat has two wires from the furnace, and the furnace control board has terminals only for those two wires.
The fan for the furnace is controlled by a temperature sensor and 120-volt relay mounted to the firebox enclosure. We'd like to run the fan when not running the furnace to distribute the pellet-stove heat throughout the home, but to do so means going into the furnace room and pushing the relay override button. There doesn't appear to be a pre-wired way to control the fan from the thermostat (which does have a fan control switch).
My questions: 1. Is there any harm in running the furnace blower nonstop? 2. Is it possible to change the control board on the furnace to include low-voltage fan override? And if so, is this cost-effective?
A. There should be no problem running the fan all the time. (Be sure it is permanently lubricated, or oil it as required, and check the filter and replace it frequently.) This is known as CAC -- constant air circulation -- and it is used to keep the temperature more even throughout the house.
As to the electrical connection, you need to have a licensed electrician do that for you.
Q. About three years ago, my husband and I had our bathroom remodeled … new vanity and new plumbing fixtures. About three weeks later, we noticed a bad odor coming from the sink. Our plumber was cooperative and put in a larger trap and even resealed the toilet. Still the odor. This is Delta, bought at an exclusive plumbing store. When notified, they said they never heard of the problem and sent us a new drain stopper. The odor continued. We have tried vinegar, bleach and cleaners from the Home Depot. While the cleaners worked a little while, the odor is getting worse.
Can you suggest anything, or do we have to take out this plumbing and install new plumbing? We never had this problem while living in this house for 45 years and raising two daughters.
A. If the new sink is made of molded fiberglass or some other plastic, it may be responsible for the odor. I have heard from readers with similar problems. Your older sink was probably ceramic, and odor-free.
If you are able to determine for sure that the sink is the culprit, you may want to consider replacing it with a ceramic one.
Addendum: In answering a reader's question in an earlier column, I said that if a furnace is located in a crawl space, the reader should consult with his HVAC contractor to determine if one of the crawl space vents should be left open to provide the needed makeup air for proper combustion.
My good friend, an internationally known engineer, author of several books and much-sought lecturer worldwide, offered the following comment: "Saw your column today and have a comment …
"Having the air intake for HVAC in crawl space is bad! What is needed is to duct the intake out to fresh air …"
• Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Write to him in care of the Daily Herald, P.O. Box 280, Arlington Heights, IL 60006, or via email at email@example.com. His book, "About the House," is available at www.upperaccess.com and in bookstores.
© 2012, United Feature Syndicate Inc.