Replacing a door in an existing door frame is easier and much cheaper than pulling out the trim and frame and installing a prehung door, because you have the old door as a template.
Carefully align the top and hinge edges of both doors and clamp them together.
Use a speed square and a sharp pencil to transfer the hinge locations to the new slab.
Unscrew the hinge and tape it in place to trace the rest of the hinge outline. Be sure to match the distance from the edge of the door to the edge of the hinge (the same as it was on the old door).
Chisel out the opening, leaving the corners for last. Then use a sharp utility blade to score around the corner radius. Pop out the corner slug with the chisel.
The kids shouldn’t have been playing floor hockey indoors with a real puck because those babies can go right through a hollow-core door. But the damage is done and now somebody (i.e., you!) has to replace the door. You have two choices. Yank the old door and jamb, trim and all, and replace with a prehung door. Or, spend less time and save money by installing a blank door slab in the existing jamb and leave the trim intact. Hanging a slab is easier than you think. All you need is a hammer and chisel, clamps, a square and a drill and a hole saw. Measure the width of the old door. Sizes are all standard, so you’ll be able to find a replacement at the home center.
Line up both doors and lightly clamp them together (Photo 1). Next, mark the new slab (Photos 2 and 3). Mortise the hinge openings using a chisel and utility knife (Photo 4). Once you’ve finished mortising the hinges, set the door upright and bore the lockset holes.
If the old door was trimmed at the bottom and you were happy with the gap at the floor, cut the new door to match. Mount the hinges on the new door and hang the door. If you don’t need any further adjustments, remove the door again, then finish it to match the rest of the woodwork and rehang it. Now it’s on to the next item on your fix-it list.
Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.
Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.