There might be more to this window pain than poor installation

Q: Three-and-a-half years ago, I had double-pane vinyl windows installed. Last summer, I noticed big black ants through an opening on the upper inside of the window frame of my south-facing window. The exterminator said they were carpenter ants and drawn to moisture. I did not have them anywhere else in the house.

Then, last winter, with very heavy rains and wind from the southwest pelting that window, I had heavy leakage from the same place, and another spot on the upper inside frame of the same window.

The window representative at first told me they guaranteed their caulking for only one year. But eventually, a couple of their guys came out and identified there had been no caulk on the underside of the flashing outside the window. They caulked it and called the job done. They also informed me the vertical wood siding above the window was squishy and needed to be replaced.

I feel that the water damage to the exterior, and possibly the inside of the wall above the window, and the carpenter ant problem were due to their installation error of not caulking. Another contractor who looked at it confirmed my feeling.

Could it have taken almost three years for water damage to accumulate enough to attract the ants?

Do you agree with the contractor's assessment that all the problems are due to their faulty installation?

My plan is to call the window company and request they open up the wall, repair any internal water damage and replace the damaged siding. I'd just like a bit more confidence in my request.

A: Coincidentally, it takes about three years of water leakage to attract carpenter ants, so that correlation sounds very plausible.

Lack of caulking can certainly cause leakage, and routinely does. Unfortunately, this window installation requires caulking to remain leak-free. Ideally, the flashing should be able to do the job alone, but with retrofit window installations, this is much easier said than done, depending on the situation, roof covering, exposure to weather and so forth.

Window retrofitting is a very challenging business, but there is no excuse for missing critical caulking. The squishy siding above the window sounds as if it may in fact have been a preexisting condition, based solely on its location.

Certainly you are justified in asking them to open up the wall and check for damage due to the carpenter ants and missing caulking. But I would not be surprised if you had other issues from older windows, or something else leaking or holding water above that window, which they should not be responsible for.

Further, three years is a long time to come back and repair something without an extended warranty of some type. So I think cooperation with the window company to find a reasonable way to split cost and responsibility would be the way to go.

Darrell Hay is a local home inspector and manages several rental properties.