How To Install Interior Window Trim. Repeat for the opposite jamb. Now you can install the two vertical side pieces of trim.
Use a wood plane sander or. A reveal will create a shadow. The first thing to do is to mark the reveal on the jamb extensions.
The first thing to do is to mark the reveal on the jamb extensions.
Match it up to the miter joint on the window trim you installed earlier. Measure and crosscut the window stool to length from 1x4 primed pine. Make a corresponding 45-degree cut and. Place a side casing against the wall aligned with the reveal line on a side jamb.