Minisplit drain - Carpenter Ant Highway ?

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peakbagger

Minister of Fire
Jul 11, 2008
8,835
Northern NH
I live in the woods and carpenter ants are an ongoing battle. I use the Max Force squeeze baits that have Fipronil as the active ingredient in areas where they have been in the past and it seems to work pretty well. I was late in applying bait this year and noticed some ant activity so I took a good look around the house. My minisplit has been installed for close to ten years with a flexible drain pipe down to the ground. Over the years the end has been covered with grass and a bit of dirt. Yesterday I noticed ants going up and down the outside of the tubing. The tubing runs into the PVC chase that hides my tubing and control wiring and eventually heads up the wall and then goes through the wall. When I pulled the tube I could see it mostly plugged with dirt but an obvious tunnel running through it. I got out my bait and applied in a few spots. its usually takes a few days for the workers to haul it into the colony and kill it so I will keep an eye on this area.

The bizarre thing with carpenter ants is they sometimes nest quite a far away from the ground. I have found nests in the deck between my first and second floor in an area that was not moist or damp. It was obvious that they just picked a spot where they couldn't be disturbed.
 
Yeah, I found a huge nest of carpenter ants in the attic of a cottage I was fixing up.
 
Perhaps create a wet trap in the drain line to prevent the ants from getting in?
Simply terminating the drain in a small container filled with water that is allowed to overflow might work.
 
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Carpenter ants will journey 300 feet or so from their nest to find new sources of food, water, or a new spot to build their nest. I've found them in cedar shingles that were covered over with asphalt shingles on a roof. It's nothing for them to run up a tree or down a utility line to a house.


Maxforce and Advion are both very good baits.
 
I just cut a huge nest out of the second floor sill plates a few days ago. We kept seeing them occasionally since we got here but couldn't find the nest. Four studs and about three feet of second floor sill plates had been taken by the ants as a nest. I would definitely check your chase very thoroughly. Carpenter ants also cycle between carbohydrate and protein based foods. If they aren't in the mood for sweet stuff, they won't take sweet bait like Terro. We initially found this nest after we demo'd some drywall and pulled out the pink R19 insulation. After we pulled out the insulation near the nest they made a run for it with their eggs. I got most of them with a shop vac and dumped them along with bits of wood into a dumpster. The survivors that didn't get vac'd were found nearby in a pile of rotten wood that also came out of the house. For those that might not know, carpenter ants don't actually eat the wood, they just remove rotting/rotten wood and live in the remaining dry wood.
 
They may not eat wood, but they certainly carve out solid, dry wood to make tunnels and spots to raise their babies. The wood does not have to be damp or rotten for them to do this.
 
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begreen said:
They may not eat wood, but they certainly carve out solid, dry wood to make tunnels and spots to raise their babies. The wood does not have to be damp or rotten for them to do this.
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Interesting, I had no idea they could eat dry wood as well. I'll definitely keep an eye out, but I think we got all of them out of the parts of the house we just fixed.
 
In the cottage that I found them in they used dry vertical corner members at the ground floor to start and remain hidden, then traversed in the attic loft to the location of their eventual mega nest site. I think they may have started out in damp wood near the foundation sill plate. The place had been unoccupied for a few years and unmown. But they worked their way up through dry wood. I had to replace the corner studs and window framing on that side. The damage was extensive.
 
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begreen said:
In the cottage that I found them in they used dry vertical corner members at the ground floor to start and remain hidden, then traversed in the attic loft to the location of their eventual mega nest site. I think they may have started out in damp wood near the foundation sill plate. The place had been unoccupied for a few years and unmown. But they worked their way up through dry wood. I had to replace the corner studs and window framing on that side. The damage was extensive.
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That sounds almost exactly like what happened to my house. I saw roots growing through the dirt where the sill plate against the slab used to be all along the eastern side of my rectangular house. It was pretty horrifying when we saw the full extent of the damage and the size of the nest.
 
I have a piece of pink foam insulation board, one side is flat and looks like it came from the store. Flip it over and its full of tunnels and is swiss cheese. It was in the corner of a box sill and the end lined up with a nail hole through the outer rim joist. They came in through the hole and just tunneled there way in. My house is modular on the first floor and the ceiling dry wall is glued to the ceiling joists with foam. I would hear scratching noises in my ceiling on quiet nights. The second floor was unfinished for several years but was decking over with plywood. I finally took out saw and sawed a hatch in the floor and found a nest about 8 feet in from the outside walls. They came in at the sill and had a any highway up a wall cavity and then chewed tunnels in the foams between the ceiling and several ceiling joists before they built a nest.

Two side of my house has foam board with stucco on the exterior. I had a lot of ant issues on that side of the house. They were tunneling through the foam from the ground up the foundation wall to the sill. The only exterior trace were a few holes where they dumped their frass from tunneling. I ended up cutting a 2" wide strip at the top of the foam below the slll and founds lots of tunnels. I dusted the top ofthe foam for a few years and that seems to have knocked them out. Some folks broadcast a zone of death with the latest insecticide that isnt banned around their house and wood piles. I believe in just baiting the potential entry points yearly.
 
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peakbagger said:
I have a piece of pink foam insulation board, one side is flat and looks like it came from the store. Flip it over and its full of tunnels and is swiss cheese. It was in the corner of a box sill and the end lined up with a nail hole through the outer rim joist. They came in through the hole and just tunneled there way in. My house is modular on the first floor and the ceiling dry wall is glued to the ceiling joists with foam. I would hear scratching noises in my ceiling on quiet nights. The second floor was unfinished for several years but was decking over with plywood. I finally took out saw and sawed a hatch in the floor and found a nest about 8 feet in from the outside walls. They came in at the sill and had a any highway up a wall cavity and then chewed tunnels in the foams between the ceiling and several ceiling joists before they built a nest.

Two side of my house has foam board with stucco on the exterior. I had a lot of ant issues on that side of the house. They were tunneling through the foam from the ground up the foundation wall to the sill. The only exterior trace were a few holes where they dumped their frass from tunneling. I ended up cutting a 2" wide strip at the top of the foam below the slll and founds lots of tunnels. I dusted the top ofthe foam for a few years and that seems to have knocked them out. Some folks broadcast a zone of death with the latest insecticide that isnt banned around their house and wood piles. I believe in just baiting the potential entry points yearly.
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My wife thinks it would be best to remove all the foam from around the house. After finding that giant nest, I don't disagree with her anymore. Do you think we will suffer any frost heave? We are leaving all of the foam that's under the ground, we just want to remove the stuff that sits against the vertical edge of the slab. We've been digging out around the house in preparation of rebuilding the sills/walls and backfilling with clean stone.
 
peakbagger said:
I would hear scratching noises in my ceiling on quiet nights.
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That is what clued me in to the carpenter ants too. Before that I had no idea they were there.
 
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SpaceBus said:
My wife thinks it would be best to remove all the foam from around the house. After finding that giant nest, I don't disagree with her anymore. Do you think we will suffer any frost heave? We are leaving all of the foam that's under the ground, we just want to remove the stuff that sits against the vertical edge of the slab. We've been digging out around the house in preparation of rebuilding the sills/walls and backfilling with clean stone.
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When I had the foundation installed in 1987 I put 1" of foam from the footings to just about ground level and backfillled.The plan was to put the above ground foam in later as it would get scarred up during construction. A year or two later I installed foam on the exterior on two sides of the house and put a stucco finish on it it took a couple of years before I noticed the ant issues. I never did the other two walls and realized I had a good amount of heat loss of those two walls. I ended gluing 4 ' lengths of foam on the inside walls from the sill down that were not insulated on the outside. It made a difference heating wise. I am living with the foam on the outside walls as it would be difficult to add foam on the interior as there is lot of stuff in the way. Foam on the edges of the slab is important as without it there is lot of heat loss at the slab edge but I think the trade off is the owner has to be proactive on setting out baits to keep the ant population in control.

Due to this ant issue I would be hesitant to recomend the Insul block foundations unless someone has bombproof ant shield method.

The other odd thing with the walls with the foam outside and the stucco is that some critter over the years has been stripping off the stucco. There are very obvious strips that look like the critter went back and forth and stripped every bit of stucco.
 
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Look into porkies. They'll go after salt in the strangest places. Any really weird chewing that makes absolutely no sense can often be attributed to them.

Can you post pics of that foam board?

Bomb proof ant shield... If I was building a house or opening up the walls, I'd treat the structure with Bora care, and the bays with a dessicant like Cimexa.
 
When I worked in a mill I used a insulation for heavy duty service called foam glass for underground and areas where there may be moisture. It would be interesting to see if ants would try to next in it. I expect they would not. It cost more than foam.
 
It took awhile to find this This is a carpenter ant nest in pink foam board that was located in a dry box sill in the interior of the house. It was covered with foil faced insulation. The corner broke off when I pulled it out but was similar to what is left of the panel. They had been in there for several years as its in a hard to reach corner.


P6240220.JPG P6240219.JPG
 
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semipro said:
Perhaps create a wet trap in the drain line to prevent the ants from getting in?
Simply terminating the drain in a small container filled with water that is allowed to overflow might work.
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Might not work either. I observed ants "swimming" into one of our hummingbird feeders yesterday. They enter the feeding holes at the bottom and enter the sugar water reservoir inside.
 
semipro said:
Might not work either. I observed ants "swimming" into one of our hummingbird feeders yesterday. They enter the feeding holes at the bottom and enter the sugar water reservoir inside.
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They did not just crawl up the tube they crawled on the outside of the tube. I will be taking a look today to see if there are any more of them since I baited them last Wednesday.
 
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Wow, that's what my second floor sill plates looked like!
 
EatenByLimestone said:
Wow! It takes a while in order for them to do that!

Were you seeing them inside in winter?
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No really but I was always finding them in the spring and summer but I think it was from another nest in sill under door that I eventually needed to fix.
 
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