Salvaged wood doors are like secondhand suits—for a perfect fit, you'll probably have to do a little tailoring. Make any cuts with a circular saw—one with a sharp blade and guided by a straightedge clamped to the door. (Cutting a door on a table saw is too dangerous and hard to control.) As a general rule, your work will look best if you line up the door's latch hardware with the existing hardware and strike plates on the other doors.
Big Doors for Small Openings
These doors are the easiest to fix because you just cut them down to the size of the opening. Plan your cuts to preserve the door's proportions. For instance, if a door is too tall, trim a bit off the narrow top rail and a bit more off the wider bottom rail. If a door is just a little bit too wide, remove the hinges and trim the hinge-side stile only. But if you have to trim off both sides, you'll have to reposition the latching hardware. Remember to leave a 1/8-inch gap at the top and each side of the door, and a 1/4-inch gap at the bottom.
Small Doors for Big Openings
If a door is too short or too narrow for its opening, a filler strip or two needs to be added. Here's how This Old House contractor Tom Silva makes a seamless alteration on a painted, solid-wood door. (A wood door with a clear finish allows no room for error, either in workmanship or wood selection. If it's worth the effort, have it fixed by a millworker with the mindset of a furniture restorer.)
