I know I said I'd never write about it again, but it is that time of year, after all, so:
I have algae on my roof and am confused about the proper way to control it. I have had contractors who would use a special machine. I have read about spraying on chemicals, then rinsing. I have also read about zinc strips to control the buildup. What is the best solution?
Roofers nail copper or zinc strips at the peak of the roof above the portion affected by the black algae. When it rains, water reacts with the strip, and what is produced continues down the roof to kill the algae, and the stain disappears. Many roofers believe copper is better, but zinc is what most suppliers sell.
Other metals also appear to work to some degree, though not consistently, they say.
The obvious question, of course: Is the black algae, or the green mildew, damaging your shingles? The mildew simply makes your roof slippery to walk on, one roofer said, just as it does bricks and wood decks.
Black algae? Among roof shingle manufacturers, the consensus is that the black algae is an aesthetic problem only, or minimally affects long-term performance. While some reports suggest that algae affects asphalt-shingle life by eating away and loosening the granules, the process of cleaning the algae is probably more detrimental than leaving it on.
Black algae is ugly, however, and that’s why homeowners want to get rid of it. Some roofers use a product called Shingle Shield, www.shingleshield.com, which the manufacturer says contains no bleach or chlorine.
The active ingredient is sodium hydroxide, also known as lye or caustic soda, which requires the user to don protective clothing — mask and goggles, too.
Power washing with the stuff at the lowest, gentlest setting possible is the way to go. You don’t scrub, because it disturbs the granules that protect the shingles, and that will surely shorten the life of your roof.
That is all. Ask me again in two years.
ARE YOU MOVING?
Here are some tips to keep the folks who are hauling your belongings happy, from the American Moving and Storage Association:
Provide the essentials. Consider the crew’s needs and comfort: Offer access to drinking water, designate a bathroom for their use, and keep hand sanitizer available. Have disposable paper towels handy, to save your linens and other items from the possibility of moving-related grime. And you might want to identify an outside area where smoking would be permitted.
Keep kids and pets busy. Make arrangements to keep small children and pets occupied so they don’t get in the way. If possible, have them stay with friends or relatives at the time of the move.
It’s food for thought: Most crews greatly appreciate coffee in the morning and the offer to pick up a fast lunch, since it’s time-consuming to close up the truck and cumbersome to maneuver a tractor-trailer around a typical downtown area.
Castor oil or peppermint oil is a natural rodent repellent. Castor oil or peppermint oil has an asphyxiating effect on rats, mice, chipmunks, moles, squirrels, and shrews. A cotton ball with four to five drops of either oil placed where mice appear (and out of reach of cats and dogs) should be sufficient to chase them away.
The attic, a pipe chase, garage, and basement are good locations for such treatment. Obviously, the repellent does need to be occasionally replenished.