Drywood Termite Treatment – Chemical vs Heat Tenting Pros & Cons?
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A relative’s house has a drywood termite infestation.
They have been advised they need to tent the house for treatment, and given an option of a heat treatment or a chemical treatment.
Other than the obvious inclination to avoid chemicals when there are other options, what are the pros and cons of each?
Does anyone know of a reliable non-biased source of information to evaluate the options?
Does anyone with experience with either have any relevant info to share – anything you wish you had know before you did it?
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Given the temperature extremes necessary, I would be prepared to find drywall cracking, floor finish cracking, and finish crazing on some surfaces. Those things might be preferable to pesticides, but I don't know how realistic it is to raise a whole structure to insect killing temperatures, hold it there, and expect no cosmetic changes.
The heat treatment temperature is reportedly 120-140 degrees F. The termites are supposed to die at 120 F, so the 140 F is to get the inside of the wood to 120 F. That does not seem overly extreme - attics get to those temps all the time. I would suspect snowbird homes in Arizona routinely reach 120 F over the summer when the residents are out of state and the house is not being cooled...
> The heat treatment temperature is reportedly 120-140 degrees F. The termites are supposed to die at 120 F, so the 140 F is to get the inside of the wood to 120 F. That does not seem overly extreme - attics get to those temps all the time
Attics do not have finishes. It's also why you don't store valuable items in them.
It might all be fine, in which case, awesome.
But if weird things happen, I wouldn't be surprised.
There's also a time dependency to this whole operation. I suspect most of this rapid heating is accomplished with propane heaters, which give off tons of latent heat as well.
Rapid changes in humidity relative to ambient temperature could cause condensation where you don't want it (either when temperature is ramping or when it's tapering off).
Not saying this is the wrong solution, per se... but the amount of heat (and duration) to get all framing members to the kill temp must be formidable.
I wouldn't leave my books, electronics, perishable foods, wine, etc. during this process, so why would I blindly assume it's okay for everything else?
All in all, you're proposing temperature differentials that outside trim/siding materials have to endure and those installations are often specified with gaps on the order of 1/8" to 1/4" to accommodate seasonal expansion.
I can promise you that a well done kitchen cabinet crown molding package is not installed for that sort of expansion/contraction (nor should it be).
Heat treatment is used pretty routinely for bedbugs and I don’t think there are routinely extensive damage reports. Though perhaps you could get more info regarding finish durability and anecdotal evidence by researching that. It does seam like certain structures would work better/worse depending on framing member size and heat sinks. Often times you can get good pest data from local or regional college entomology departments, though I doubt they’d be able to talk about finish stability. Also anything in your car has most likely experienced those temperatures on a hot summer day.
Also they don’t usually introduce high temps, just longer durations. I think they duct in close to 120-130 degree air with specialty heaters.
> Also they don’t usually introduce high temps, just longer durations. I think they duct in close to 120-130 degree air with specialty heaters.
This is a 50-60 F degree swing from normal temps. It's substantial. Wood moves. Finishes crack.
All depends on what you care about.
I suppose it also depends on whether it happens or not
Several years ago we had our house "heat treated" for bed bugs (unknowingly brought them back in our pillows from a hotel stay). The one thing I did notice was that the veneer glued onto the edges of some of our furniture had come loose. It didn't fall to the floor, but it was definitely loose and had to be glued back on. Not a huge ordeal but something to note. More importantly, the joints in the furniture were fine and the actual finish was fine. I didn't see any problems with drywall or flooring.
Also, for the heat treatment to work (with bedbugs anyway), you have to empty the contents of every drawer, cabinet, closet, etc... in your house. The heat has to get into every corner and crevice. It looks like your house has been raided by the most thorough burglars in history. Just be mentally prepared to walk back into a house where everything in it has literally been turned upside down. But after trying for months to get rid of them ourselves, it was worth it. One and done.
Hopefully it's as effective on termites. Good luck.