Sealing window openings starts with a sloped sill on the rough opening.
A first pass with fluid-applied fills in nail holes and the joint between the sheathing and framing.
This is followed by a zig-zag pass, which is smoothed into a continuous bed covering all the surfaces of the rough opening.
The fluid-applied laps onto the face of the wall to create a “gasket” into which the window flanges are fastened. The author installs horseshoe shims to create a drainage gap along the bottom flange.
Once the flanges are screwed on, a final layer of fluid-applied is applied on top of them.