I have stairs going to a walk out basement. The door to the stairs was a standard 36x80 interior door. I wanted something more robust for security so I bought an exterior door. It says 36x80 but its not. My old interior door is about 91.5cm wide and this new exterior door is about 90.8cm wide. I have a significant gap that I can see through. The hinges are recessed on both door and frame. option 1. install the hinges in new non-recessed spots and reclaim some distance that way. option 2: run a new small strip of wood inside the frame for the hinges to be drilled into. I am really annoyed that 36 inch doesnt mean 36 inch. This is more frustrating than PVC and CPVC sizes not matching.