Now that the insulation is complete the next step is to install jamb extensions on all windows and doors. Jambs are the part of the window or door that extend from the actual window out to intersect with the finishwall material (drywall, wood, ect). Windows and doors typically come from the factory with jambs that are made for 2x4 or 2x6 framed walls. Our walls are 7.25" deep so this requires custom jamb extensions. I am building ours out of 5/8" clear (no knots) pine and using pocket screws and glue to attach them.
Backside of jamb extension with pocket screw visible
Finished side of jamb extention
Using the pocket hole jig
In this video I have a horizontal component of a window jamb extension. I am using the jig to drill a series of angled pilot holes in the backside of the extension. I will then attach this piece to 2 vertical jamb extensions and another horizontal piece (using pocket screws). This will result in a 'picture frame' box that has the exact dimensions of the window. This box will be aligned with the existing factory jamb, glue is applied between the two, and pocket screws are inserted in the pre-drilled holes on the back side of the extensions and screwed in.
