Fix a split door jamb

Why door jambs split

A door jamb is the thin board that lines the opening, and the strike plate the latch catches on is screwed into it. Behind the jamb there's a small gap of shims, then the wall framing. When a door is kicked or slammed, all that force lands on the strike screws, which are often only about 3/4 inch long and grip nothing but the thin jamb, so the wood splits along the grain.

The repair has two parts: closing the split so the wood is whole again, and moving the strength into the framing so it doesn't happen twice. Glue does the first part, and long screws or a metal reinforcement plate do the second. On an exterior door, reinforcing the strike also makes the door harder to force open.

Common causes of a split jamb

Let's fix it

1. Check how bad it isLook at the split and the trim beside it. A crack along the grain near the strike, with the pieces still attached, is a good repair. If chunks are missing, the wall framing behind it is cracked, or the door no longer closes squarely in the frame, part of the jamb may need replacing. On an exterior door after a break-in, check the hinge side and the deadbolt strike too.
   Done

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2. Remove the strike and trimUnscrew the latch and deadbolt strike plates. If the split runs under the casing, the trim around the door, pry it off carefully with a putty knife and small pry bar, working from the end so it doesn't crack. Pull or snip any nails left in it.
   Done

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3. Glue the splitGently open the crack a little with a putty knife or screwdriver and work wood glue deep into it with a syringe or thin stick. Get glue on both faces of the split. Wipe off what squeezes out with a damp rag.
   Done

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4. Clamp and screw it closedClamp the split closed if you can reach both sides, or press it closed by hand. Drill pilot holes through the jamb on each side of the split and drive screws to pull it tight, countersinking the heads below the surface. Let the glue set for the time on the bottle before putting stress on it.
   Done

   Something went wrong?

   • The screw pulls the jamb crooked Back it out a turn; add a shim behind the jamb before driving it again.

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5. Reinforce the strikePut the strike plates back using 3-inch screws in at least one hole of each, so they reach through the jamb and shims into the wall framing. Drive them snug, not so hard that they pull the jamb out of line. For more strength, install a metal strike reinforcement plate, a longer plate that spreads the force over more of the jamb, following its instructions.
   Done

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6. Fill and sandFill the screw holes and any remaining crack with wood filler, overfilling slightly. Once dry, sand it flush and wipe off the dust.
   Done

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7. Reinstall the trim and testNail the casing back on with finish nails, set the nails and fill the holes, then prime and paint the repair. Close the door and check that the latch and deadbolt catch smoothly. If the latch now misses the strike, we have a guide for a door that won't latch.
   Done

   Something went wrong?

   • The latch misses now Move the strike slightly, or file the strike opening.

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Watch it done

How to Repair a Door JambBy HowToWith GEO on YouTube. Their method may vary a little from ours.

Watch on YouTube

If the door still won't latch

If the door sticks or won't latch after the repair, see the guide for a door that won't latch.

If the hinge screws just spin, check our guide for stripped door hinge screws.

Split door jamb questions