New door likely to need trimming before placement

Q: My son got angry and kicked a hole in a door and now I get to replace it. It is a hollow interior door that is flat with no panels. I would like to just take the door off the hinges and install a new door rather than install a more expensive, prehung door. How difficult is this?

A: Hollow-core, interior doors are inexpensive to replace. However, getting them to hang just right is a different matter altogether.

To start, measure the door and buy a replacement door at a home center. It is likely that the door you purchase will be slightly larger than the one you are replacing. Don't worry about that, you will just have to trim it.

Unless you have some specialty tools, buy a door that comes prebored for the handle and latch. Next, remove the doorknob by removing the two screws that keep it secured to the door. The screws may be visible, but most likely you will have to remove a coverplate on one side of the doorknob. Lift it off with a standard screwdriver and remove the screws.

Knock the hinge pins up and out, and lift the door off. Remove the hinges from the door and set them aside.

At this point, you are going to use the old door as a template to mark and cut the new door. On a hollow core door, only the edges have solid wood. This gives the hinge screws and doorknob something to bite into. It also gives the hollow door some rigidity.

Lay the new door down and then lay the old door on top of it. Make sure the holes for the doorknob are aligned and the front edge is even. Use a pencil and trace around the old door to make lines on the new one. You should only need to cut a sliver from the back edge of the door. If you cut too much, the hinge screws won't have anything to bite into. If your door isn't a standard size, you may have to order a custom door.

The best way to trim the back edge of a door is with a table saw, but a circular saw with a guide works equally well. Use a circular saw to trim the height of the door, but make sure that you don't change the position of the doorknob hole. For example, if the doorknob hole is 35 inches from the bottom of the old door, make sure it is in the new door as well.

When the door is cut to size, it's time to mortise the hinges. In this case, mortising refers to cutting the exact depth of the hinge into the edge of the door so that when the hinge is screwed in, it sits flush with the door.

Stand the old door and the new door on edge so that the doorknob holes are aligned and facing down. Mark the locations of the hinges on the back edge of the new door.

The quickest and most accurate way to cut a mortise is with a router and a hinge template. However, if you don't plan on doing a lot of woodworking, forego the expense of these tools and go with a faithful standby: the hammer and chisel.

Take the hinge and trace its outline in the locations you marked. Be sure that the hinges are in the same locations as the old door.

Tap the chisel along the outline to cut the edge of the mortise. Then take shallow passes to remove the wood inside of the outline. Occasionally, test the depth of the mortise by inserting the hinge. If the hinge is not flush, remove more wood until it is. Repeat for the other hinges.

When the mortises are all cut, screw the hinges into the mortises. Stand the door up and re-hang it by aligning the hinges and installing the hinge pins.

Test the swing of the door. If it sticks along the top or side, use a block plane to smooth out the contact point. It is likely you will have to tinker with the door to get it just right.

Reinstall the handle and latch and make sure they contact the strike plate.

If it doesn't latch, leave the door alone and move the strike plate. It's much easier than re-cutting the hinges.

When the door operates to your liking, put a coat of paint on it.

Michael D. Klimek is a licensed contractor and president of Pro Handyman Corp. Questions may be sent by e-mail to: questions@pro-handyman.com. Or, mail to: 2301 E. Sunset Road, Box 8053, Las Vegas, NV 89119. His Web address is: www.pro-handyman.com.