carpenter bees in basement


I have a problem with carpenter bees in my basement year after year. I have vinyl siding over wood siding. Can’t locate where they are coming in. Could they be coming in under siding in holes in basement wall which is a stone wall? What would I look for outside to find them?

I tried Bee & Wasp spray along the perimeter of the ceiling around the top of the wall of basement. This only works for a short time. I kill about 50 bees per year. Can you help?

This is an easy one. If you read the answer I posted about carpenter bees going under vinyl siding, you’ll learn this is an all too common problem when wood siding is covered with vinyl siding. As the post explains, the bees will still be able to smell the decaying wood hiding underneath and gain access to it through small seams in the siding. Once under the siding, they’ll drill their holes and be successful at developing to mature adults.

Now the real problem is these nests won’t be easy to detect because the wood is covered. In most of these cases, you won’t see any of the typical signs because the bees are drilling under the wood. This means the sawdust won’t be seen and neither will the holes they create.

And as fall turns to winter, they’ll move into these holes and overwinter in a nest that is very well protected from the outside cold. This means they’ll be quite comfortable with a good chance of surviving and entering the home.

So come the new year and the spring when they become active, they’ll try to emerge to go foraging outside but because the siding is tight and tough to escape, many will end up moving to inside the home. So my best guess is the nests that are harboring hibernating adults and pupae are releasing them in the spring and that some of these are finding their way into your home.

The good news is the treatment to stop this is easy and highly effective. Basically you’ll need to dust along every row of the vinyl siding with Drione Dust.

This can be done with a Hand Duster and/or a Dustick depending on how easy it is to reach the siding. If you read up on Drione, you’ll learn it’s highly effective against carpenter bees and lasts a long time. So for you home I would recommend a thorough dusting in the spring and then another treatment with Drione in the fall.


Hand Duster:


If done right, you should expect immediate results. In other words, I expect you could knock out the existing nests immediately and the residual of the Drione would keep new nests from forming all summer.

And if you dust again in the fall, you should be protected throughout the entire winter so that any coming around to hibernate won’t be able to survive in the abandoned nests. This should keep them away from your home and out of your basement.

Lastly, even if you do a good job of dusting this spring, I strongly recommend you spend some time going around the outside of the home looking for any carpenter bees flying around soffits, overhangs, gutters, etc. Now if you find bees in any of these areas, I would expect these areas would be entry points. So to make sure they’re not using them as entry points, you’ll need to treat them with the Cypermethrin talked about in our article here:

Carpenter Bee Spray:

No doubt vinyl siding can present a bit of a problem when treating for nesting bees but it’s nothing a good amount of Drione Dust can’t handle. And since this treatment will work on all pests, it’s a great way to stop anything that might want to nest under it. Get your siding treated as explained and I’m sure you’ll be able to knock out any carpenter bee nests present and keep new ones away all summer.

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Comments on carpenter bees in basement Leave a Comment

April 27, 2013

Julia Heath @ 3:21 am #

Your info on treating was very helpful, but the bees have bored a hole in my vinyl siding and I was wondering if there was any difference in treatment on vinyl or wood? Do you think the tunnels are in the vinyl or have they found wood under the vinyl?

May 2, 2013
May 3, 2013

Robert E Rommel @ 3:16 pm #

I live in a brick home. I have carpenter bees that are entering through holes in the mortar between the bricks and obviously nesting in the wood in the walls. I sprayed as best I could with insect killer, and I seem to have eliminated the bee problem for now. But there is no way to see where the bees are nesting because it’s inside the wall behind the brick. I see that Drione is the best remedy for these carpenter bees, but how can I address this issue with Drione behind the bricks? Should I close up any holes in the mortar? Thanks.

May 6, 2013

Jocelyn X. Hurley @ 4:54 pm #

I’ve had an ongoing problem with carpenter bees drilling holes in overhangs that are on all sides of my house. I’ve been spraying with the Cypermethrin and it’s worked quite well but I’m wondering if there is something else I can do that’s more permanent. What if I add some to the paint I use on my trim and siding? How much would I need? I generally paint every 4-5 years (a lot of touch up for sure) and if there is any way I can incorporate a chemical with the paint I’d do it.

May 8, 2013
May 16, 2013

Amanda Y. Flynn @ 11:44 pm #

What if bees are still flying around eaves after vinyl siding has already been put on?

May 21, 2013
June 16, 2013

Katrina Sweeney @ 12:55 am #

I shot a puff of Drione into the air at a wood-boring bee that was coming after me. It left me alone. I sent a puff into the bee holes in my porch posts and haven’t seen any bees since. I also puffed around areas of the house where ants are. It’s been successful so far. I sent puffs up the siding because an exterminator who came last year said the dust will go behind the siding where I’ve seen ants go. Seems to work. I need to figure out how to get the squeeze right with the bellow so more puffs of dust, rather than a stream of dust, comes out of the bellow. I’ll definitely order more before I run out of this container.

June 19, 2013
June 17, 2013

Orville Banks @ 3:53 pm #

What if bees are still flying around eaves after vinyl siding has already been put on?

June 19, 2013
July 4, 2013

Darnell Garrett @ 3:12 pm #

Recently there were a good number of ant colonies in the basement and I couldn’t figure out where they were coming from so I sprinkled some around the corners of the basement and around the basement door and cracks and holes. I even dug a few small holes and sprinkled a little dust and ever since I used it I didn’t see any sign of ants except dead ones. I had to sweep hundreds of them! I never thought Drione dust would work this well. Highly recommended.


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