How to fix a split doorjamb

When a door is kicked in, the stress falls upon the doorknob latch and the deadbolt latch. This is not a difficult repair to complete, but it does take some carpentry skills.

Q: I recently had a break-in at my house. The intruder kicked in my front door, which split the jamb where the door latch locks. My friend and I want to replace the jamb ourselves but fear we will get in over our heads. After all, this is a matter of security.

A: This is not a difficult repair to complete, but it does take some carpentry skills.

When a door is kicked, the stress falls upon the doorknob latch and the deadbolt latch. Usually that force splits the strike side jamb somewhere above the deadbolt strike plate and somewhere below the doorknob latch strike plate. The interior door molding also is broken in this same general area since it is attached to the jamb.

To decrease the chances of the doorjamb splitting and allowing an intruder to enter, you can install an armored strike plate.

You also should check the door to see whether it is split. If so, you may need to replace it or fit it with a steel door reinforcer (about $15), which wraps the area of the door at the location of the deadbolt and doorknob, giving it more strength.

Your first step is to remove the broken interior door molding and discard it. Also, remove the exterior brick molding, which can be reused, so be careful. You can use the claw end of a hammer, a pry bar or even a sturdy screwdriver to do this; just don't damage the surrounding walls.

After the molding has been removed, you’ll need to remove the damaged jamb. It will be attached to the framing with several nails. The best tool for this job is a reciprocating saw with a bimetal blade. This setup cuts through nails and wood easily. If you don't want to buy or rent this tool, use a hacksaw blade to cut through the nails and a hammer to coerce the jamb out of its position.

This jamb also will be attached to the head jamb and may be attached to the threshold. The nails used to attach the jambs together will probably be inaccessible, so try cutting the strike-side jamb in half and carefully pull out each half without twisting the other jambs.

Once the damaged jamb has been removed, install the replacement jamb (about $40 at a home improvement center). You also will need to replace the broken interior molding. While you are at the store, pick up a can of spray foam insulation (about $10).

Next, measure and cut the new jamb to length. You may have to chisel out a portion of the stop to get it to fit with the head jamb and/or threshold.

Predrill nail holes about every 12 inches down the length of the jamb. Fit the jamb into position, making sure it is flush with either side of the wall opening, so that when you install the molding there are no significant gaps.

Once you are satisfied with the jamb's fit, plumb it with a level. Insert wood shims between the doorframe and the jamb and nail it into place. I prefer 16d finish nails for strength, although 10d nails are just fine.

Nail the first couple in halfway to secure the jamb in place, check the fit and finish nailing completely by countersinking the heads under the surface of the wood with a nail set. Fill in the surface holes with wood putty.

Spray the foam insulation between the frame and the jamb to stop any drafts. Cut and fit the new interior molding and reinstall the brick molding with 4d nails. Caulk the seams with paintable silicone caulking.

Finally, cut the holes for the door and deadbolt strikes. Close the door and mark where the holes need to be drilled to accept the strikes. Use a drill to bore the holes and a chisel to clean them up.

Paint the jamb and molding to match.

Normally, the manufacturer provides ¾-inch screws to attach the strike plates to the jamb. However, you might try 3-inch wood screws to secure all the way through to the doorframe. It may make the difference between burglary and vandalism.

Mike Klimek is a licensed contractor and owner of Las Vegas Handyman. Questions may be sent by email to [email protected]. Or, mail to 4710 W. Dewey Drive, No. 100, Las Vegas, NV 89118. His web address is www.handymanoflasvegas.com.