Dana ... it's a 2x4 framed wall with brick exterior on first level. I'm going to replace the entire window unit, inside and out. I'll order a new window to fit the RO with room to trim with new vinyl brick mold to seal up against the brick, etc.
Thanks, Larry
Most brick-clad 2x4 framed walls have a wood or fiberboard structural sheathing, and a 1/2 to-2" air gap or cavity between the sheathing and the brick. The cavity should be vented to the exterior both top & bottom, through weep-holes in the mortar every few bricks at the base, and at a minimum comparable slots in the vertical mortar at the top course of brick. That allows the cavity to drain, and convects super-moist air created by sun on rain/dew wetted brick to escape to the outdoors via convection rather than condense/adsorb into the structural wood.
In a cavity wall, first the
rough window opening gets flashed to direct bulk water into the cavity, on the exterior of the asphalted felt/ paper covering the sheathing. If the structural sheathing is asphalted fiberboard (Celotex, etc) it gets flashed to the exterior of the fiberboard. If it's plywood or plank sheathing without any weather resistant barrier such as #15 felt, it needs to be directed to the exterior of the brick, even at the rough opening. This guy has pictures
what appears to be a decent job of flashing the rough openings into the cavity on a brick veneer using purpose-made tapes. (You can buy EPDM flashing tape in a few widths from box stores.)
The finish window's bulk water handling features are all designed to drain to the exterior of the brick, not into the cavity.