I have a 12 year home with a large foyer window 6'X6' square with a 3' radius half moon window above it. I recently noticed condensation in the hlaf moon for the first time and also just noticed minimal condensate starting near the bottom of the 6'X6' window. I have been in home almost 4 years and have cleaned windows inside and out 1-2 times a year, would Windex attack the seal in any way??? I have noticed that caulking outside looked a little worn (where vinyl frame meets window), would this cause the problem? I would think the actual seal is somewhere below the vinyl frame. Also, is there any way to remedy this without direct replacement? I had a crazy idea I could recaulk to attempt to seal everything, then drill some type of access hole, then purge out inside of window with nitrogen (or argon) and seal the access hole. Any ideas?, thanks in advance.

I am planning on installing trim around some existing windows. This is in a new house and they trimmed the windows with drywall except a simple stool and apron. My plan was to remove the drywall to the studs and install wood jams and a header as well as a new stool, apron and of course casing. I just want to make sure this is the right way to go about this. I plan on using 3 1/2“ fluted casing with solid corner blocks (this matches my fireplace surround). In my living room I have 3 windows next to each other (about 11" between each) and was planning on making a continuous stool and apron but casing them separately. Do I sound like I am on the right path? Also when you use fluted casing what style trim would you use for the apron? Thanks in advance for the help. Steve