It's best to close off an unused chimney

Q. I am having cellar and chimney problems with my approximately 60-year-old house. We have no water problems in the cellar. First, since installing natural gas many years ago, the chimney has not been used. Now, the material around the bricks on the bottom, probably cement, is flaking off. I can see the brick, which seems to be intact.

The top of the chimney is not covered. Should it be? The second problem is that there is a lot of white powder forming all around the cellar. I use a dehumidifier in the summer. In the winter, I hang my laundry to dry in the cellar. Any information you can send me will be greatly appreciated.

A. The mortar is flaking off because it absorbed moisture that froze and caused it to spall. This did not happen while the chimney was in use because the heat from the heating appliance kept it warm and helped dry it. If you have no intention of ever using the chimney again, it is a good idea to have it covered; that might help.

The efflorescence forming around the cellar is an indication that there is moisture in the masonry. There may not be enough to cause a leak, but there is enough to dissolve the salts in the block or concrete foundation. As the water evaporates, it leaves the salts behind, and that is what you see. Efflorescence can be brushed off easily, but it will come back as long as the cause of it is not removed.

I don't think that drying your laundry in the cellar is the cause of it; to cause efflorescence, water in liquid form is needed to dissolve the salts contained in all masonry, and not the vapor from drying clothes. Besides, an old house needs moisture, whereas newer, tight houses would suffer from it.

In the spring, take a critical look around the foundation and take care of any low or flat spots in the grade that allow water to stand close to it. Add good soil to slope the grade away from the foundation and plant grass. My recommendation is to obtain a slope of 2 inches per horizontal foot for as far as you can, if possible. The limitations are that you must not have any non-pressure-treated wood in contact with the soil, and that the soil should be kept at least 6 inches away from such wood.

Q. We recently read your recommendations re: using a washable reusable filter for furnace/AC. Please advise who the manufacturer is and/or where we can purchase. A quick check in Home Depot had one filter that was $20. Is this what you referred to? Thanks, and your column is wonderful.

A. You should be able to get washable filters in any hardware store. They are more expensive than the disposable ones but can last for many years if taken care of properly. The other option is, of course, to buy disposable filters and replace them several times a year, but they end up in the landfills, and that is not very ecological.

Q. A woodpecker has pecked away at my cedar shakes, about 20 feet up both sides of our house. He has left quite a few small holes. Our exterminator said that termites do not go up that high and he sees no evidence of ants. What do you think is causing this, and how do I prevent further damage once I have it repaired? When should I repair it; i.e., now that it's winter should I wait until late March? Thank you in advance for your help.

A. I am surprised that your exterminator didn't mention that the woodpecker is looking for insects like cluster flies, etc., that look for shelter from the winter's cold in any cracks or crevices they can find. And there are plenty around cedar shakes. I am also surprised at the comment that termites don't go that high; they can start feeding on the cellulosic material wood provides and work as high as they want to.

To keep insects such as cluster flies from taking shelter in your siding, you can have an exterminator spray the south and west walls of the house in late August or early September. You may want to consider calling another pest-management professional, as it seems that the first one may need some more experience and training.

If you do not live in an area where bears are a problem, you can also offer the woodpecker an alternative by hanging suet on a tree near the house, but be sure that you remove it before warm temperatures in the spring, as the suet would turn sour and sicken any birds coming to feed on it.

The repairs can be made at any time, and if you apply a stain to the shakes, it will make them less appetizing.

Q. Many years ago, I made my two-car garage into a playroom. I put a wooden floor over the concrete and installed asphalt tile over it. I now need a new floor. I considered laminate flooring. The first installer I called in said he could do it and it would be perfect. The second installer said he would not even try to put down a laminate floor because the floor is not level. He used a level at various areas of the room. He said it would be a disaster. He suggested vinyl tile or sheet vinyl and mentioned a vinyl that has padding attached under it. There is over 500 feet of flooring. Do you have any ideas about what I should do?

A. The second installer seems to have made a more thorough investigation, and if he is a dealer in laminate as well as vinyl flooring, there should be no reason to suspect that he is trying to convince you to stay away from material he does not handle. You would be wise to listen to him. Sheet vinyl with a foam backing sounds like a good suggestion.

Q. I am an avid reader of your column. A recent column addressed the problem of waterproofing basements walls. I realized after reading your advice I had made an error in using DRY LOCK waterproof coating to prevent moisture seeping through the walls, especially at the joints. After reading your article, I am now concerned with water being stored inside the cinder blocks. I applied the waterproof coating on the walls inside the basement. You mentioned water stored within the cores can wreak havoc within the living quarters above. Please describe what havoc I should expect and look out for. Also, what would you suggest to remedy my error before anything happens to the living quarters above?

A. My warning applies only to foundation walls made of hollow units - like cinder blocks, concrete blocks or clay tiles. Water getting inside untreated blocks leaks inside the basement or crawl space, but if the blocks are waterproofed, water cannot escape and builds up within the cores. It slowly evaporates into the living quarters above. The worst example I have ever investigated was a four-apartment unit where the cinder block foundation had been waterproofed with a cement-like white coating to keep the basement dry so tenants could store their belongings.

Over time, the apartments became unlivable. Black mold developed on the walls and ceilings; the tenants' possessions, including furniture, were covered with mold, and the stench was unbearable. Everyone moved out. I need not go into what followed, except to say the apartments had to be gutted and redone.

A simple remedy for you, as it was in the above case, is to drill holes at the base of the vertical joints of the bottom course of blocks just above the floor to allow any water to drain out. Do not use an electric drill. If water gushes out, you may get electrocuted; instead, use a star drill and a hammer.

If you have a serious water problem, to keep the basement dry, you have several choices. The most effective is to have a waterproofing contractor install a fiberglass "gutter" against the block walls that catches the water and leads it to a sump pump; but that is expensive.

Do-it-yourself methods can include adhering a pressure-treated two-by-four on edge to the concrete floor an inch or so away from the walls; building a cement curb in the same place; or ripping in half a U-shaped vinyl gutter and adhering it to the floor upside down - with all of the above leading to a sump pump.

Q. My husband and I have had substantial renovations done to our home (both interior and exterior) over the last eight months. Some of the renovations included building three interior walls made of tongue and groove pine board. The walls came out great and look beautiful but my husband and I are disagreeing on how we should treat these walls. Can you tell me if there is a "need" to do anything to these walls at all? I just love the natural look of the pine but my husband insists that we should stain or urethane them for protection. One wall is an entryway to our basement; therefore it could possibly retain marks from our hands, scratches from moving things up and down the stairs, etc. The other two walls are in parts of the house such that they will not be subject to touching, scratching, etc. Also, how does pine "weather" outside? Is it similar to untreated cedar which turns gray with time?

A. It is best to apply some preservative coating to the interior walls to protect them from fingerprints, shrinking, swelling or cupping, etc., and oxidation. It will not protect them from scratches. You can apply a natural coating, such as Watco or Minwax, or a tinted one, or a polyurethane coating. Outdoors, pine will turn black if exposed to any moisture. It should be sealed with an appropriate coating at regular intervals.

• Henri de Marne's column appears Sundays. He 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 e-mail at henridemarne@gmavt.net.

© 2009, United Feature Syndicate Inc.