Posted by Don from York PA on 14:00:33 3/22/2010 from 220.127.116.11:
I've found your site to be quite helpful and informative, and I have a difficult situation with carpenter ants that I'm hoping you might be able to help me with.
We have a FourSeasons aluminum, wood, and glass sunroom built onto the back of our house. It is built on a masonry foundation, with a Conservadeck floor built over a crawl space. Conservadeck is structural flooring that consists of 6" of styrofoam sandwiched between two layers of 1/2" OSB. The bottom (exposed) side is clad in aluminum. Last Spring (April 25th, to be exact), we discovered large winged carpenter ants congregating in the sunroom - perhaps a 100 or so. I tracked them down to an outlet that is installed in the floor of the Conservadeck. I pulled the outlet and 6" round junction box out of the floor to find a series of tunnels, and the beginnings of a cavern chewed into the styrofoam. Further investigation and excavation revealed that the inside bottom layer of OSB was damp, as well as the pressure treated sill plate that the Conservadeck is attached to.
I vacuumed up the ants - our central vac is the lead weapon in our war on carpenter ants (we live in the woods, this is not our first encouter). I had the sunroom guys come out to inspect the room, and refurbish the joints, seams, and caulking. The design of the aluminum framing that holds the sunroom glass is such that it should direct any water that might get into the aluminum channels out to the weep holes. I suspect the water is due to condensation from outside (or inside) air infiltrating the void in the Conservadeck.
The current situation is this:
1) Removing the electrical outlet and junction box have given me about a 6" hole through which I can access the expanding "cavern" underneath the floor.
2) I have excavated some of the chewed up styrofoam down to the top side of the bottom OSB, and to the edge of the sunroom where the sill plate is located.
3) I can get my central vac nozzle and hose into the "cavern", and can suck up ants from that end.
4) I have located at least some of their entry points to the house, and have monitored their activity at night.
5) I've used (what appear to be ineffectual) carpenter ant traps placed in the "cavern" over the past year. Just this past week, I started to see activity again - since it just got warmer. I put in new traps about two weeks ago.
I don't see a way that I can eliminate the moisture without disassembling the portion of the room that sits on the Conservadeck, replace the decking, and reassembling the room. I might need to do that at some later time, but it will be a costly and time-consuming propostion. I realize that as long as the moisture is there, that I'll likely have ants.
As an aside, when I installed the room, I took out an exterior sliding glass door that turned out to have a nest of carpernter ants in the vinyl-cald frame. I had the exterior wall covering off at the time and was able to look around for additional evidence of ants, and found none. And yet, they seem to have found their way back in.
So, I'm looking for a way to best manage this problem. I suspect the answer involves chemistry and vigilance. I have this "convenient" void in the floor, with easy access (and easy isolation) that I can use to place baits, traps, etc...
Any guidance you could give me would be greatly appreciated.
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