Keeping Your Home Carpenter Bee Free

Carpenter Bees rarely cause structural damage to homes unless they have been drilling and nesting in the same wood for years at a time. More likely damage will happen when woodpeckers hear the Carpenter Bee larvae in the nests and then start to damage the wood in order to get at a tasty meal.


Treatment as related to Carpenter Bees usually means taking control of the nesting areas by eliminating the bees or using products to repel the bees.

When to treat: (1) It is a good idea to treat in the spring, when bees are first observed, (2) again in mid-summer to kill any bees which may not have acquired a sufficient treatment when they emerged, and a third time in early fall to contact any over-wintering bees occupying the tunnels.

Carpenter Bees like many other bees are very effective pollinators. Currently, there is a global shortage of pollinators which is threatening  farmers’ livelihoods and our food supply.  Due to this concern, please consider pesticide-free alternatives when treating Carpenter Bee nests.

Pesticide Free Treatment and Prevention

Carpenter Bees emerge in early Spring from their nests and start to collect pollen.  On sunny, warm days, Carpenter Bees, both male and female, will leave the nesting holes. The females who are the active drillers will collect pollen to bring back to the nest, which will eventually feed the young.  At this time, you can safely use a coat hanger to eliminate any larvae in the nesting site by inserting the wire into the nest and breaking up any larval activity. Coat the holes in almond oil or NBS 30. Once that is done plug the holes with a small ball of aluminum foil and caulk the holes with wood caulk or fill in the hole with a wooden dowel.

To further prevent Carpenter Bee nesting, spray NBS 30 Insect Repellent, a mix of plant oils that makes wood smell unpleasant to Carpenter Bees as well as drilling wasps and ladybugs. Apply the repellent after plugging the holes in early Spring. NBS 30 can be mixed with water for a temporary (30-60 day) topical solution or mixed with wood finish (always in the last coat applied) for a longer term repellent solution.

To provide alternative nesting options for Carpenter Bees, drill 1/2″ holes in wood blocks and hang them in sheltered areas around your house and deck. The bees will often decide to nest in these blocks, rather than trying to re-drill nests in the fascia and soffits of your home.

Pesticide Treatment and Prevention

Prevention may be accomplished by an insecticide additive like Bug Juice added to standard paint or log home finishes on new structures or when maintenance coats are needed and will eliminate bees.

Treatment as it relates to elimination of Carpenter bees which have already drilled into a structure, involves steps recommended by entomologists which are effective in reducing future nesting activities.

In early Spring, obtain a pesticide, product containing carbaryl (Sevin), cyfluthrin or resmethrin. Insert this in the nesting hole. Wait for the bees to exit the hole, then plug the hole with aluminum foil and either caulk the hole with wood caulk, or use a wooden dowel. Avoid inhaling the insecticide or contaminating your clothing with the spray. Always stand upwind from the surface you’re treating.  Treated tunnels should be sealed with a small ball of aluminum foil and caulked with log caulk, wood putty or filled with a wooden dowel after 24-36 hours.

In conclusion, not everyone has the same level of issues with Carpenter Bees. Unfortunately, when even one hole is evident it should be treated with the full extent of treatment recommended for prevention. Treating one time and forgetting about it does not work! Monitor the situation from year to year in order to stay on top of the issue. An ounce of prevention………




Finishing new wood? Read on for essential tips.

When logs go through the planer, as most new,  smooth wood does during the milling process, the heat of the planer melts the natural sugars in the wood creating a barely visible film called mill glaze or mill scale. This little talked about film creates a barrier that interferes with the penetration and adhesion of wood finishes, which in turn can create long term issues with finish durability and performance.

When wood finish is applied to lumber that still has mill glaze, penetrant stains will often look spotty and show a decrease in performance. Film forming glossy or satin finishes may start to peel soon after application, have a spotty appearance and decreased durability and performance against the elements. To protect your investment initially and avoid costly re-do expenses, it is extremely important to remove mill glaze from wood before applying any type of finish.

Removing mill glaze can be done in a number of ways; suggests the two options below:

1.Washing with a wood cleaner:

The easiest way to remove mill glaze is to wash with a wood cleaner designed to remove mill glaze and clean wood. Wood cleaners formulated specifically for use on wood will maintain the proper pH balance of wood while removing mill glaze. Cleaners that contain oxalic acid, like X-180 Weathered Wood Restorer or sodium percarbonate like All Wood Cleaner do a great job of removing mill glaze. Most products that remove mill glaze are best applied with a pump up sprayer and then washed off with a pressure washer at no more than 500-600 psi. Do not use bleach unless specifically recommended by the wood finish manufacturer. Bleach is caustic and dramatically affects the pH of wood, which can cause spotting, streaking and all manner of application problems.


2. A light sanding:

If you have the people power and/or a small surface to remove mill glaze from, use a fine to very fine grit sand paper to give the wood surface a light sanding. After sanding, be sure to use a vacuum or leaf blower to make sure all the sawdust from sanding is removed from the wood. Even small amounts of fine sawdust left on logs can cause a lot of problems when staining, preventing stain from being absorbed and creating an uneven finish. This results in decreased finish performance and durability.

Removing mill glaze is the essential first step in a quality wood finish application. Questions about your specific project? Leave a question in the comments section below, send us an email at [email protected], or give us a call at 888-208-2248.