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Boring Bugs

There are signs of wood boring bugs in my timbers. The main concern here in mid-coast Maine are carpenter ants and powder post beetles, not termites, and whether the damage is old versus active. Certainly there have been remnants of bugs, such as surface channels or tunnels, in areas of large timbers with some bark left from the original milling. Since it is in an isolated area and the timber is otherwise sound i have assumed that the damage occurred long ago and is not an issue. Given the many years and variety of ways wood can deteriorate, how can you tell? Exposing the sheathing boards on a late 18th century farmhouse revealed tunneling, sawdust etc. but an exterminator suggested that there was no recent activity and to spray a nest if it was discovered. – a downeast Maine reader

I’m not sure how far downeast you are, but I, personally have found active termites in Brunswick , Maine , four years ago. They seem to be moving a little further north (and east along the coast) each year.

It is possible to determine if powder post beetles are active by looking for piles or “streamers” of frass (like very fine sawdust) coming out of their surface holes that are about 1/32″ to 1/16″ in diameter, although the frass may be just sifting out of old holes. You can determine old holes from new holes by marking out a section (perhaps 1′ x 1′) and marking each hole with a pencil. Then check it again after a time (a month, a year, five years, etc.) to see if there are new holes. New holes indicate active infestation.

I often find active carpenter ants by listening for them with a “mechanic’s stethoscope.” This device is just like the doctor’s stethoscope, but instead of a cup at the end, it has a long, thin metal rod. Auto mechanics use it to listen for parts knocking inside a running engine. You can get one at most automotive suppliers for about $20. When I use it for detecting ants I place the end of the rod on a board or timber. I can easily hear them chewing on the wood, sometimes 3 to 5 feet away from the stethoscope. This is best done in the middle of the night when they are more active and the ambient noise is less.

John Leeke is a preservation consultant who helps homeowners, contractors and architects understand and maintain their historic buildings. You can contact him at 26 Higgins St., Portland, Maine, 04103; or by E-mail:; or log onto his website at:

© John Leeke

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