Trimming a Door

Q: What’s the best way to shorten a door? We recently installed new flooring in our kitchen, and I have to cut the bottom of a door to accommodate the increase in floor height. Can you give me advice for marking and cutting accurately?

A: The first thing to do is set the door more-or-less back in place and measure the distance between the top of the hinge pockets in the door frame and the top of the hinges themselves. This figure, plus the bottom-of-door clearance required, is the amount you need to cut off your doors. Allow for a 1/4-inch to 1/2-inch gap, though you may have to adjust this later, depending on how the door swings. After totaling the amount to be cut off, apply masking tape to both sides of the door in the cut zone (to reduce splintering), then pencil a cutline across the door. My preference for trimming doors is an orbital action jigsaw. This tool is easily controllable and causes minimal splintering. You could also use a handsaw, too. If you absolutely have to use a circular power saw, consider clamping a strip of scrap wood along the top of the cut line. This eliminates the splintering that this tool might otherwise cause. Hang the door on its hinges again, and swing it through the full range of travel. If the door hits the floor anywhere, lay a pencil flat on the floor and slide its tip along the door face to scribe a new and higher line for trimming again.