Sealing no-flange windows in a REMOTE wall retrofit
I’m planning to insulate my 60 year old house from the exterior using the REMOTE approach.
We can’t afford to replace all the windows so I hope to re-use the existing windows which are all wood framed but show no signs of rot. Some are single pane and some are double pane and I believe they’re all no-flange windows. We’ll use a combination of interior and exterior storm windows to boost the thermal performance of these old windows.
I’m thinking about how to air seal and manage bulk water at the the window-to-framing interface. Most REMOTE examples I’ve seen use a flanged window which seems to make it easier to tie flashing into the wall membrane/WRB. However I’ll be working with our existing windows so these examples aren’t as helpful. After removing all the siding and trim, I’m proposing to remove each window unit and flash all around the RO, then re-install the windows. This should leave a small gap between the wooden window frame and the flashed opening. To seal this gap I’m thinking about installing foam backer rod, and then caulking from the interior with something super flexible. Then I’m thinking of applying low expansion spray foam around the window frame on the outside for added protection. Should any of this ever leak, I figure the flashing on the RO would drain the water away.
Is this a reasonable approach when trying to re-use no-flange windows or is there an easier or cheaper method?