Steven L. Smith, Bellingham, WA Home Inspector (King of the House)

I have posted before about anobiid beetles and the damage they can do here in the Pacific Northwest in a damp, unventilated crawl space. The home buyer's question is always the same: Are they still active? Sometimes the damage they have done is so extensive that that concern becomes a moot point -- all the wood needs to be replaced already. However, the inspector cannot always tell which wood requires replacement and which does not. As the WSDA says: it is the job of the inspector to identify anobiid activity and to refer to a contractor and/or a pest control operator. Anobiid damage can be subtle and it is not within the constraints of a home inspection to determine the extent of damage to all wood. The inspector is looking for clues and will then call in the specialists. There are other times when the wood seems to be pretty good at the time of the inspection, but the crux of the matter is can it be kept that way when the pest's exit holes are apparent. Sometimes it is obvious that they are active: The crawl space is moist (moisture content in the wood reads 13% and above); there is a fine frass visible outside the exit holes (recent emergence holes); or in general there are numerous conducive conditions that make it more than likely that the pest is still working. However, once in awhile, an inspector will see a crawl space where some such exit holes exist, but there are very few conducive conditions. In fact, the seller might say that work was recently done, to try to eradicate the pest.

In that situation, there are a couple suggestions I give to clients. These were provided to me years ago by a professor who studies the species over at Washington State University. It is not a quick fix, but he suggested that a person could locate a spot in the lumber where many beetles had been exiting over the years. It is easy to find and is readily apparent by the number of shot-sized exit holes. He said to either glue a piece of paper flat on the face of the wood or, easier yet, draw circles with a permanent marker on an area with many holes. Beside that, write the number of exit holes enclosed within the circle.

The concept is simple enough: If they exit through the paper, you know because they leave new holes in fresh paper. And, when you count holes in the circles, if there are more holes than there had been, then you also know they are active. I have made a little illustration below to demonstrate the use of the circle. I reiterate, this photo is designed to give an example only. In fact, the number of exit holes in this wood make me think that, in real life, it would be so unsound as to be in need of replacement. Regardless, it was a handy photograph that I could put circles on and it does quite nicely illustrate the concept. You would write beside the yellow circle thirty-one and by the white circle you would write twenty-one. In a year or so, this is not a speedy process, you would go down and check again. More holes mean the beetles are still alive and working. Personally, I would check it for at least a couple years before I would be convinced that they were inactive and I would make more than one circle. I would do a number of them, as it is easy to do and that will be more comprehensive as a test. The species takes five years to get going but, once they are established it is most likely that a few will exit every year. Of course, lumber can be treated for the anobiid beetle by a pest control operator but lots of people do not want to use chemicals if in fact the cure can be achieved by natural means of drying out the crawl space such as ventilation, providing a vapor barrier, eliminating runoff water, eliminating plumbing leaks, etc.

                   31 holes                                              21 holes

By the way, if the wood looks like this.....you are probably too late to be counting holes. Replace it.

Thanks for counting on me.

Steven L. Smith

Bellingham WA Home Inspector

www.kingofthehouse.com