# Spray Insulation as Carpenter Bee Deterrent



## kentx6 (8 mo ago)

I am building a new climate-controlled shed with the beams and joists above ground by about 2 feet. I know that carpenter bees are a problem in the area and wonder if closed-cell spray insulation would provide effective long-term protection against carpenter bees. I see from other posts that you do not want to seal existing holes with expanding foam, but this is new construction without any existing holes. Thanks for your help.


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## Thom Paine (Nov 24, 2021)

I learned by accident..... Carpenter Bees don't like Boiled Linseed Oil coatings... stops them from attacking the wood...
Dilute the Oil with turpentine or mineral spirits 50/50.
Discovered by coating a deck that was fine dining for the bees... until it was coated. 
Might be an idea for you.


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## SW Dweller (Jan 6, 2021)

Painting might be a better method. I remember that they seldom burrow in painted wood.


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## Thom Paine (Nov 24, 2021)

SW Dweller said:


> Painting might be a better method. I remember that they seldom burrow in painted wood.



That's what the Linseed Oil is.... 
and it is absorbed into the wood.


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## SPS-1 (Oct 21, 2008)

kentx6 said:


> I see from other posts that you do not want to seal existing holes with expanding foam, but this is new construction without any existing holes.


I don't know for sure, but I would not risk it.


I have read that carpenter bees are not bothered by latex paint, but they won't want to bore through a good layer of oil based paint.
When I built my deck, I took that a step further and coated the underside of the joists with a brush on roofing tar.
Carpenter bees might go into the side of a joist, but they particularly like to bore up from the bottom.


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## Steve2444 (Sep 28, 2020)

I spray the underside of the deck with *bifenthrin* every couple of months, seems to work well.

I also made some carpenter bee traps, although they mostly only work in the spring and fall, when they make the holes for nests and then to winter over.


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## icerabbit (9 mo ago)

Closed cell foam, does not stop them, but rather may give them a medium to live in. Certainly old stuff. The house we bought, has an elevated sun room - like a deck above a walk out basement, that was enclosed - which was insulated with closed cell spray foam underneath. While doing other work, one could see lots of round holes going vertically up into the foam insulation. Nothing as far as recent activity or current activity. But certainly lots of holes.


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## mark sr (Jun 13, 2017)

I've been fighting carpenter [aka borer] bees since I bought this place in 1991. I've seen them bore thru paint/stain both latex and oil. Even seen them bore into PT wood a few times. Other than a direct hit the best thing I've done is take a duster and blow sevin dust into their chambers. It both kills any adults in there along with the eggs when they hatch.


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## SPS-1 (Oct 21, 2008)

Carpenter bees love pressure treated wood.


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## SLSTech (Jan 19, 2021)

Closed Cell can help with other insects - i.e. preventing them from smelling / detecting moisture & food. For carpenter bees NBS 30 additive


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