Keeping Wasps Out of Unvented Soffits
My house is a 30-year old timber frame house with open ceiling (no attic) – SIP panels for walls and roof. The soffits -most likely vinyl – are not vented. In the past couple of years the wasps have been getting into the soffits to build their nests leading to some intrusion of the wasps in the closest rooms. Most of the time I noticed the external activity before finding any wasp inside the house. The nests are most likely built in the space above the soffit as there are no visible nests in the house. Calling the pest company every year to spray their entrance into the soffit – once I find heavy activity from the outside – does not seem to be a good long term option – by the time you called them, the nest is already well established. Once the nest dies, a bad smell spreads to the closest room. Early spring I caulked the entrance path to 2 nests that were active last fall. I am not quite sure that will really help in the future or if it could be really done around the entire roof overhang. The result of this early caulking resulted in an increase smell coming into the house…which later subsided but seems to have returned recently. Are there any good solutions to limit the entrance of wasps into a soffit?
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I’m giving your question a bump. It seems like a tricky situation! I asked my colleague Brian Pontolilo your question, and this is what he suggested:
Run an insect screen along the bottom of the blocking used to fasten the soffit material. Blocking along the house and back of the facia also works. Basically you need to close off the gap where insects get in. As for a screen product, I found this recommendation from another GBA reader: http://www.mcnichols.com. He says, “Over the years, I've come to rely on stainless steel, heavy-gauge, insect screen. Same hole size as regular insect screen, but thicker gauge and a ‘forever’ product.”
Kiley- Thanks for the reply. In my case the structure of the overhang is a SIP panel, and I am assuming the soffit is primarily attached to the facia and the external wall panel (I have attached pictures taken during the construction by the former owner). In any case , if I understand correctly, the solution would be to install the stainless steel mesh screen above the soffit so it covers the entrance. I also considered that removing the soffit will provide access to the area where the wasp build their nests and it will also provide the opportunity to seal any opening between the wall and the roof. This is not a job that I will be able to do myself but I am trying to figure out all the details before I find a contractor.
In terms of the soffits in this case, is there any argument to be made for replacing them with vented soffit?
I had a wasp issue in a soffit couple years ago. Basically, if there is a gap, they will get in and nest.
Also note that they don't hibernate over the winter, they die off and the next sort of stays there withers away.
So I think your best solution is to climb up there this spring, take your soffit completely out, get rid of the nests/clean out the area. Caulk the wall-roof joint. Staple up mesh if you I can as a backup measure and re-install the soffit. While you're up there you can colour-match caulk any seams in the soffiting as well.
Jamie - Thanks. That sounds like a good plan.
Hey, Jacques. My neighbor had a similar issue. He was really sick and tired of wasps, but he had no idea how to get rid of them. As far as I remember, he eventually called a https://enviropcs.com.au/ , so he could feel relieved. So, if I were you, the first thing I would do is to kill those pests. Tbh, I really hate them. I love bees ‘cause they are really useful, but wasps are just useless. Anyway, I hope you’ve already solved your problem. If you have, then tell us about it, please. I’m really curious about it.
Carpenter bees, those big huge bumble bee looking things that bore into your wood siding and soffits are not useful and quite damaging. They don't sting but stare you and buzz at you and come back year after year because they hibernate.
I tried many different approaches including traps, sprays etc. What finally worked for me were the insect foggers used for spiders etc. in basements. I waited until the fall and put the spray nozzle into one of the holes and let it fill up the void. I used a few cans in different holes and they haven't been back.
As I have had some follow up questions on this post, I will provide a status. The wasps (not carpenter bees) were clearly building their nests in the soffits (see attached picture).
Even though they were treated externally by a pest company 2 years in a row, they were coming back.
Like I said, I did follow the recommendations provided by jberks. The nests were cleaned, a stainless steel mesh was wrapped up and stapled inside, and then the seams in the soffit were caulked. This work was done in August last year and wasps have not reappeared in these treated soffits.
Since then, an air leakage analysis performed last winter by Peter Yost has shown significant air leakage coming from the roof/wall joints. As I still need to put the mesh in most of our soffits (only few have been fixed), I will also need to address the air leakage in those joints. Instead of replacing the old foam or using caulk, the current thinking is to use flashing tape to wrap up the joints.
Wow. A picture is worth 1000 words.
Can you please share with us how big the gaps were through which the wasps were getting through into the soffit?
The wasps were getting into the gaps/spaces left by the indentations of the soffit (two of those entry points marked in blue). The exterior caulking of the soffit entailed to fill of those gaps.