Some door frame repair is simple, while in other cases the process may take you several hours to complete. It may mean adding some door frame shims to help the door hang level, or you may have to replace damaged wood in the frame. In any case, door frames with problems are not lost causes. If you have carpentry skills and basic tools, you should be able to complete a door frame repair project on your own.
Open and close the door to see if it is binding. If the door is catching on the lower portion of the latch side of the door, try inserting a thin piece of wooden shim behind the upper hinge. If it catches on the upper side of the door frame, slip the door frame shim in behind the lower hinge.
Remove the door from its hinges. Remove the hinge plate from the door frame where you used the temporary shim. Place a wooden shim of the same thickness behind the hinge plate, and then screw the hinge plate back into position. Hang the door. Make sure it's not binding any more. If it still is, repeat the process and change the shim size.
Replace the wood in the door frame. Sometimes the wood splits or rots making it necessary to repair. Remove any weather stripping that's on the door frame. Take off the inside door casing with a pry bar. Try not to damage it, or you may need to replace it. Take off the striker plates for the door latch.
Cut away the bad door jamb. Set your circular saw to a depth that can cut the door jamb away from the door frame. Don't cut too deep. You can't cut all the way to the top or bottom of the door jamb with the circular saw, so remove what remains with a wood chisel.
Measure how much pine wood you need to replace the old door frame. Cut it out. Mitre the ends to fit in with the existing frame.
Set the board in place. Use a level to make sure it is plumb with the door. Add door frame shims as necessary between the board and the wall of the house to make the board plumb. Once it is straight, nail the board and shims in place with 2-inch (5 cm) finishing nails.
Drill holes for the striker plates for the latch in the board. Attach the striker plates.
Caulk all the seams. Replace the weather stripping. Paint or stain the door frame to match the rest of the door. Reattach the casing to complete the repair.