Air infiltration in vinyl windows with integrated J Channel
SO I bought a new house (new to me, built in 2001). The windows are vinyl and they have integrated J Channel. The siding is vinyl and utilizes the integrated J channel. The interior portion seems to be properly caulked and sealed, but I still get a large amount of air infiltration through the window casing itself.
If anyone has any ideas on causes i.e. not properly flashed, they would be appreciated, as would a recommendation as to how to stop the infiltration.
Generally, I don't like vinyl windows because they tend to expand and contract more than other material. It's possible the gap between the edge of the sash and the side jamb may not be tight enough. Unfortunately, if you fix that in the winter, it can expand and cause the sash to stick in the summer! What was the brand of window you used?
What kind of interior trim??? If conventional wood casing, remove a piece and see if the air gap aroubnd the window frame is sealed up. Stuffing with fiberglass insulation is not the best. I recommend DAP Foam or a non expanding urethane foam. If drywall return, checking and fixing that is a bit more messy and harder.