I’m planning how we’ll install the windows in our house build and recently read Brian Knight’s very good article in Fine Homebuilding. If you haven’t seen it, Brian has it on his website:

http://www.springtimebuilders.com/files/files/H254KN.pdf

and FHB has videos based on the article:

http://www.finehomebuilding.com/how-to/video/weatherproof-window-install-prepping-the-rough-opening.aspx

Now, in this article, after Brian installs the window he spray foams the gap (he doesn’t consider the spray foam an air barrier), then he uses backer rod followed with a quality caulk, then he uses an European air barrier tape (Pro Clima Uni Tape in his case).

I too am looking to achieve an airtight window install, and am willing to spend a little extra time & money to make this happen. I have no problem with overkill, but don’t want to be accused of excessive overkill.

If I use a quality spray foam and then use a good tape, I think Siga Corvum in my case, wouldn’t the tape provide a quality air barrier? Is there a reason for the caulk if you are going to use air barrier tape? Thanks.