Q. We installed untreated cedar shingles on the exterior walls of a vacation home in central Maryland. Now the owners are complaining that squirrels are eating the new siding. And the squirrels really are eating it — they’re not just trying to get inside the house. Is there anything we can apply to the siding to discourage them?
A. Bill Feist, formerly a wood-finishes researcher with the Forest Products Laboratory in Madison, Wis., and co-author of Finishes for Exterior Wood, responds: There are no cures for squirrel problems that are totally effective in all situations, so you may have to do some experimenting. One possible solution is to use a “taste repellent” containing thiram, a fungicide registered with the EPA for general use. Repellents containing thiram at a concentration of at least 1-to-25 have been reported to be effective on squirrels. Another repellent you could try is Ro-pel (508/888-0606, squirrel-x.com), which can be found online as well as at some garden stores. Ro-pel gives whatever it is sprayed on a very bitter taste, which may help curb the squirrels’ appetite.
One of the capsaicin-based repellents used in birdseed also might be effective. Capsaicin — the compound found in chili peppers that puts the “hot” in hot sauce — has long been registered with the EPA as an animal repellent that won’t cause unreasonable adverse effects in people or on the environment. Miller Hot Sauce Animal Repellent (800/233-2040, millerchemical.com) contains 2.5 percent (by weight) capsaicin and is a taste-based repellent registered for use on ornamentals and fruit and nut trees. Squirrel Away (squirrel-x.com), a capsaicin-based powdered concentrate, is one of the birdseed supplements. Check with your local garden centers to see which capsaicin-based products they stock — and be sure to follow all label directions when using these (or any other) repellents.
As a very last resort, you could try protecting the siding with physical barriers. (For aesthetic reasons, many homeowners won’t consider this a realistic option.) To shield corners and edges, apply metal drywall corner bead or staple up 4- to 8-inch-wide strips of hardware cloth bent 90 degrees. If the squirrels are concentrating on a small area of siding, try covering it with the wire mesh — though the squirrels will most likely just move on to an unprotected area.