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.