Log home maintenance problems can come in all sorts of shapes and sizes but here is one that we hear about at least once every summer – porcupines chewing on the logs. In fact, three times over the last two months we have fielded calls from log home owners that have had this issue. This photo is a good example of the damage they can cause.
We asked Scott Cravin (Extension Wildlife Specialist and Professor of Wildlife Ecology at the University of Wisconsin-Madison) for an explanation. Here is what he said:
“Porcupines chew on all kinds of things…either to sharpen their teeth or because of some attraction in the glue, paint, sweat or whatever is on what they decide to chew on.
Siding is usually attacked because of the bonding glue in plywood. Logs, as such, should not be much of an attraction unless whatever stain or preservative that is on them is attractive.
So….what to do? Corners and edges can be ‘armor-plated’ with angles of sheet metal, dry wall corners, hardware cloth, etc. but that may be unattractive. Repellents based on capsaicin (hot sauce is the active ingredient), thiram (a fungicide), or other mammal repellents could be applied. Even a small mesh bag of moth flakes/balls (napthalene) placed near damage may help. And there’s always the more direct approach of eliminating the offending animal. Good luck.” Scott Cravin
If your home is under attack by porcupines, you may want to consider following Scott’s advice, at least in the short run. If a porkie is gnawing off the finish on the logs, it is a good idea to take some measures to prevent it from continuing. At that point you will re-apply a good finish on your logs home. To do this you will need to sand down the logs and reapply the stain.
RELATED LINKS AND TIPS FOR LOG HOME MAINTENANCE:
Finishing log homes
Blasting log homes
A refinishing job we did in Gordon, WI
LogFinish.com has a product that has proven effective in getting rid of all kinds of log home pests. It is NBS 30. It is a citronella based product that you can add to log home finish or just add to water and spray it on. Give it a try.
A customer inquired to the Mn DNR and here is the response they got from Minnesota DNR wildlife manager Tom Rusch:
Porcupines chew on wood, whether it be cabin logs, white pine trees, or shovel handles, for two reasons: food and minerals.
In the case of live trees, they girdle, chew and eat bark to get at the cambium layer beneath the bark, which is very nutritious.
Porcupines chew on dead wood for less obvious reasons. The most common is wood handles that soak up sweat and therefore provide a source of calcium (salt). I have seen them gnaw on all kinds of shovel, ax, and rake handles. Why cabins, decks, outhouses, deer stands? They are apparently attracted to treated wood for the nutrient value of the chemicals used to kiln dry wood, and, they like the glue in plywood and oriented strand board (OSB).
In the case of your vintage balsam log cabin, it is the finish they desire, not the cabin logs. I have a cedar log cabin of similar age that has untreated logs. The porkies have lived under and in it for years and have never touched the logs! One hundred feet away the darling little miscreants have gnawed on the deck (treated and weatherized), stairways (treated, salted and weatherized), and support pillars (treated) of the newer cabin. They have also snacked on a 60-year-old weatherbeaten plywood table topped with linoleum. They spared the linoleum and metal legs, thank you, and devoured a 25 year old portable plywood outhouse instead! In the process, they denned in the “hole” for the winter and apparently used the 200 plus wood screws holding it together as toothpicks.
Physical exclusion is your best bet in this situation. Use “hardware cloth” on the logs they are chewing on. This is a light mesh wire found at any hardware store. It is the same thing we recommend for protecting live trees from beaver. It may not be as aesthetically appealing but it is affective. Lacking that, porcupines are unprotected in Minnesota and can be removed in a situation like this.