How To Install Interior Extension Jambs And Window Trim. How To Install Window Trim with Jamb Extensions Easy. Step 2 Measure the opening space to determine the width of the jamb extension needed.
This is the head trim. First we added the board that would be placed at the top of the window jamb then moved to the sides. Using a miter saw cut off head trim at 45 degree angle.
Fastened to the window casing they rest on a sill which is pocket screwed into the framing.
I personally like to use an interior glue for that. Step 2 Measure the opening space to determine the width of the jamb extension needed. We considered different composite materials but because of the potential for water damage due to exteme cold weather condensation not likely because. Add finish trim to the inside of the window nailing into the window frame and the jamb extension to.