Let new homeowners make decision about roof replacement

Q. We are about to put our house on the market and would again value your advice. Our 15-year-old shingles have serious algae stains. I've read your columns and understand the cause and remedy. Our question, though, is whether to replace the roof or clean it and insert zinc strips.

In the past few years, we've noticed tiny particles of the asphalt shingles on the deck following high winds or a rainstorm. The shingles aren't curling and we don't have any leaks. Does the "shedding" suggest that this roof is nearing the end of its life?

A follow-up question: If you suggest we install a new roof, should we remove the old shingles? There is only this single layer, but I would hate to further propagate algae under the new shingles.

A. Asphalt and fiberglass shingles have had a mixed history in the last few decades. Some have lasted close to their rating, while others have failed in half or less of their warrantied life.

Mineral granules falling off is a normal process over time and is of no concern unless the loss is so great that bare asphalt or fiberglass mats are exposed.

If the shingles are as you describe them, and there are no leaks, I would recommend you leave them alone and simply disclose their age, as you need to, in the sales contract.

You certainly can have the shingles cleaned, but you may want to talk to your real estate professional to find out if the benefit would surpass the cost. There is also the risk that washing the algae stains may damage a 15-year-old roof and force you to have to replace it.

Let the purchasers decide what color and longevity they want when the time comes to replace the roof. Zinc strips can be installed when a new roof is put on. It would take too long for the zinc strips to clean the roof of algae to be of value at this time.

I would not recommend applying another layer of shingles in climates with frequent heavy snows, and would generally discourage it in any climate. Good luck with the sale of your house.

Q. We have heard increasingly about radon, its presence and potential dangers. However, while I will admit freely my skepticism about most things, I also must admit my ignorance concerning this subject.

Is this principally a "shell game," or is it actually something about which we should be concerned?

We and our sons have resided in a home that we designed and had built some 30 years ago. To our knowledge, we have suffered no effects from radon or anything else similar to what we believe we know about it (something which one cannot see, smell or taste).

Recently, for purposes of "covering all (or most) of the bases" - security-wise - we had two tests conducted about two weeks apart. The latter, made from Feb. 3 to Feb. 5, indicated a "pCi/l" (picocuries per liter of air) of 49.0; the earlier test, made from Jan. 21 to Jan. 24 (both began and concluded in mid- to late-morning in the basement area) indicated a pCi/l of 38.7. Both were significantly higher than the ofttimes quoted "4.0."

The "fix," costing between $700 and $1,200, consists of a pipe running from below the basement floor through the roof, connected to an exhaust fan.

Is this matter truly a major, proven health concern, or just another ploy by the politicians and fast-talking "fly-by-nighters?" Your thoughts would be greatly appreciated, I imagine by many more people than we represent.

A. Radon is a gas that causes a number of cancer deaths every year. Radon is also found in water.

It takes a long time for its effects to be felt, but it must be taken seriously. If needed, remediation is essential. To get the full story on radon and its dangers to health, go to www.epa.gov/radon.

The fixes for radon are quite easy and not overwhelmingly expensive.

Reader tip: I was surprised to read your column in the Daily Herald last month with respect to a question about Corian countertops and the questioner's problem with a blueberry stain.

I'd like to say as the owner of Corian countertops for the past 15 years, his kitchen contractor was absolutely correct. Corian is a solid surface that can resist stains better than many other surfaces, and also should be cleaned differently.

Personally, I don't see the increasing love affair everyone has recently with granite, as it is a natural surface that has to be sealed and resealed frequently. Even properly sealed granite can still be stained much more easily than Corian, in my opinion.

But the true reason for my writing is this - the questioner should have been provided with a Corian by DuPont Cleaning and Maintenance Kit upon the completion of installation. Or you could have at the very least referred him back to DuPont. Each Corian countertop has its own cleaning and stain removal approach, based upon whether the countertop is matte, semi-gloss or gloss finish.

In the 15 years I've owned matte-surface Corian countertops, nearly all dirt and stains can be removed using a soapy solution or an ammonia-based cleaner. I usually use Dawn with some water and a cloth or sponge. For disinfecting, and since DuPont isn't in the habit of endorsing Dawn, they recommend one-part water to one-part bleach. But any good quality dishwashing detergent will do the job. After that, the DuPont kit and instructions list a very specific methodology, from lighter to heavier cleaning options.

Included in my kit was an initial small package of Bon-Ami, one of the best products ever developed, in my opinion, and truly a cleaner that has never "scratched the surface" it is cleaning. Also included in my kit were several different types of Scotch-Brite pads to be used based upon the severity of either the stain or the scratch or cut.

I've never used anything stronger than a green Scotch-Brite pad and a little Bon-Ami. Also mentioned in the small instruction brochure included was the suggestion of Soft Scrub if the Bon-Ami didn't prove successful.

While I wouldn't dare to question the use of your Clorox pen suggestion, I'd guess that solution involves the use of full-power bleach and the distinct possibility of perhaps creating a new, lighter stain or discoloration to the surface where the older blueberry stain was.

The distinct advantage of solid surface Corian is that it is man-made and the color is full throughout. The use of various levels of abrasives and cleansers should have no effect on its beauty and appeal.

I've had blueberry, raspberry, strawberry, wine or even marinara sauce sitting overnight on our light beige Corian countertop, and the use of a fine Scotch-Brite pad and some Bon-Ami removed both instantly without it even being obvious afterward.

A. Thank you for sharing your experience on how to clean Corian countertops. It should be helpful to my readers.

I have had, and installed, Corian tops in kitchens and bathrooms, as well as tub/shower wall linings since the 1960s, and have found the material exceptionally easy to care for. The Clorox pen is easy to use and has never caused any change in the finish of the Corian.

Interesting item: I just received a sample of a new product called Mytee Scoopy Condensation Squeegee.

Unlike most regular squeegees, it is pushed forward instead of being pulled. The collected liquid is stored in a hollow handle to be dumped or disposed of by watering plants, according to the manufacturer's news release.

The manufacturer suggests it be used to scoop condensation from windows, walls, ceilings and shower walls. However, I wonder who has significant enough condensation on walls and ceilings to be collected.

You can see more at www.scoopy.biz.

Correction: Dear readers, I have referred to oxalic acid several times as a caustic chemical. This is an error. A kind New Jersey chemist corrected me on this some time ago, but I somehow temporarily mislaid his letter, which I just rediscovered. The chemist pointed out to me that "caustic" and "acid" are opposites: caustic materials have a high pH, while acids have a low pH. He suggested I use the adjective "corrosive." Sorry it took me so long to get it right.

Interesting observation: This is in response to a recent question from a reader about basement floor drains. My original answer was that these drains are no longer recommended because people do not pay attention to them and they dry up, allowing sewer gases into the house. He wrote:

"My comment concerns regulations prohibiting drains in basements discussed in an earlier column. We lived in a ranch house for 15 years and in our present two-story house for 39 years. Both houses had basement drains connected to the sanitary sewer systems and we never had a problem with odors.

The drains were very useful for draining water tanks and the effluent from furnace humidifiers. How could these jobs be easily done without basement drains? Is the real reason for this regulation an effort to reduce extra water to the sanitary system? Is this a government solution trying to find a problem?

It would seem to be less expensive and more effective to educate homeowners to add water to the traps for basement drains. Thanks for listening."

• Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. His website is www.henridemarne.com. Email questions to henridemarne@gmavt.net, or mail First Aid for the Ailing House, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.

© 2015, United Feature Syndicate Inc.