How To Install Interior Extension Jambs And Window Trim. We considered different composite materials but because of the potential for water damage due to exteme cold weather condensation not likely because. Shims may need to be added or the plaster may need to be taken down slightly.
Shims may need to be added or the plaster may need to be taken down slightly. The extension frame will be smaller than the rough opening so it will need to be shimmed to get it centred and keep it square. I pin the jamb in place.
Space them about every 2 to 2 -12 feet apart on each of the four jamb extensions.
First we added the board that would be placed at the top of the window jamb then moved to the sides. The extension frame will be smaller than the rough opening so it will need to be shimmed to get it centred and keep it square. Cut the protruding shims flush with the edge of the drywall using a sharp utility knife. See more ideas about moldings and trim window jamb interior window trim.