I need a custom exterior door frame for my basement safe room. I have a Superior Walls basement system (Factory assembled concrete wall system) that I love. When I built the house, I had them leave the space open under my rear patio to use as a tornado room. I've never added a door to the opening, but I'm planning next years projects. The problem is the opening is rough framed with 2x lumber ripped down to the wall thickness of 10.5 inches. I know I can add an extension to a pre-framed door, but a 6 inch one? I could make a frame out of 1x12's, but how would I handle the stop with the kerf for the weatherstripping? Any better suggestions?

