Whether you’ve experienced a recent break in (or just an attempt) or other situation that resulted in a broken door jamb, it can be a frustrating experience. Once a door jamb is damaged, the door likely won’t open or close properly, which can make the doorway unusable or leave you vulnerable and exposed.
Luckily, replacing a door jamb isn’t a complicated process, and most homeowners can handle the task on their own with a few basic tools and supplies.
Remove the Hardware
The first step in the process is to remove any hardware attached to the door jamb. This includes latch plates, bolts, chains, or any other hardware items around the door frame. Often, these items can be simply unscrewed and pulled away. Once they are taken off, set them aside. As long as they aren’t damaged, they can be reused once the new door jamb is in place.
After the hardware is removed, you can begin taking off the old door casing. This includes both the door strip and the architrave pieces. Often, this can typically be accomplished either using a hammer and chisel or with a prybar. Put on your safety glasses before you begin, as pieces of the door frame may unexpectedly fly off when pressure is applied. This ensures your eyes are protected as you remove the material.
You also want to wear gloves to protect your hands. Damaged wood may splinter and can injure your hands when the material is grasped. Once all of the casing is removed, examine the opening and pull out any nails that may have broken away and stayed attached to the formerly cased area.
Dismantle the Old Door Jamb
If your door opening is surrounding by weather stripping, this will need to be removed as well. Generally, this can be removed by hand. Make sure your gloves are on when you grip the material and use a firm pulling motion to dislodge it. Once the casing and weather stripping are removed, you can begin dismantling the door jamb itself. You’ll want to start from the bottom and work your way up.
Use a prybar to pull the jamb away taking care not to disturb the threshold. If there are any screws or nails that previously attached the jamb to the threshold, either remove them carefully or use snips to cut them down. This ensures there will be space to slide the new jamb in securely next to the threshold. Once you reach the top, you’ll need to detach it from the top plate. Pull the jamb toward you and then move it from side to side until it dislodges and comes off. Make sure to leave the top jamb intact and in place, so take your time to complete this task. After the piece is removed, examine the area and pull out any nails that are still in place.
Fit New Jamb
If you’re using a kit, open it and pull out the new jamb. There will be a notched end that will be installed down towards the threshold. Now, measure the height of the door jamb area, adding about ½-inch to ensure it reaches passed the header. Cut the new door jamb to the proper size by measuring up from the bottom and marking the spot to cut. Use the straight edge or square to create a line and use a saw to make the cut.
Next, you’ll need to adjust the portion of the jamb that will sit up next to the top jamb as well as the portion that butts to it separately. Measure the inside of the door frame up to the top jamb to determine the cut for the inside lip. Mark it on the jamb using the measuring tape and square or straight edge and adjust the saw depth to only cut that portion of the new jamb. Chip off the cut piece with a hammer and chisel or by using the prybar.
Then, place the bottom into the space near the threshold, lift the header, and slide the new jamb in. Test the swing of your door to make sure it works properly. If you’re using timber, you’ll need to cut the new jamb piece to size. You may need to notch the top plate to set the replacement jamb as well. Line up the jamb and mark out the spot for the notch with a pencil and cut out the area. Once the notch is removed, place the new jamb in the space and test the swing of your door.
Leveling the Jamb
Start by placing shims at the top and the bottom of the jamb so that the new material presses against the header and threshold, and test the door swing. Based on the results of the test, shim the middle (normally near the location of any hardware) to ensure an optimal swing. Often, this means having a 1/8-inch gap all of the way around the door.
Add Starting Screws
Using the drill, place screws through the jamb and shims, and into the surrounding framing at the top and bottom locations only. Use a level to make sure the jamb is straight, adding shims and testing the door as necessary to achieve an optimal fit. Then, place an additional screw into the center shim or any other shims that were added. Break or cut off the ends of the shims.
Install Interior Door Casing
Measure from the floor to the top of the upper door casing. Then, take the new casing piece and mark the proper spot on the corresponding edge. You’ll be cutting this top section to match the existing casing, which often requires a 45-degree angle cut. This makes it imperative that you make the mark on the corresponding edge of the new casing to ensure the cut goes in the right direction.
Use a speed square to create the 45-degree angled line, making sure it is going in a downward direction with the previously made mark being the highest point and the starting location. Cut the material with a saw, following the 45-degree line. Once the casing is cut, fit it into place. Then, secure it into place using a hammer and finishing nails. Usually, around 4 or 5 nails should be sufficient to hold it in place. Fit the new weather stripping into the channel space. No tools are required, as it should just pop into the track.
First, close the door and mark the location on the door jamb where the deadbolt and knob catch meet up with the material. Using a 1-inch paddle bit, begin drilling the holes for the latches. Place the bit in the horizontal center of the jamb at each location and drill. For the deadbolt, you’ll need to drill completely through the jamb to reach the required depth. For the knob catch, a shallower hole may be sufficient. Check the reveal of your knob catch and drill to at least that depth.
Now, take the deadbolt door jamb hardware, and use it to trace the proper outside shape using the newly drilled hole as the center. Then, do the same using the knob catch door jamb hardware. Next, using a hammer and sharp chisel, remove the door jamb material within the drawn shape. You only need to achieve a depth of around 1/8-inch, so work slowly and don’t use too much force. This is simply creating a recess in which the hardware will sit.
Once the area has been chiseled away, install the deadbolt and knob catches in their spaces using the screws. For added security, you can use new screws that are longer than those that come with the hardware.
Test for Fit
After the catches are installed, close the door to make sure it secures properly and that the knob latch engages. Then, test the deadbolt to make sure it locks properly. If either latch doesn’t engage correctly, small adjustments may be required. For example, if the latches are larger or longer than the opening, you may need to use a chisel and remove more material from the center hole in the catch. Make sure to only remove a small amount of material at a time, as you want the latch to fit into the space but without too much wiggle room. Continue adjusting and testing the latches until the desired action is achieved. You can then reinstall other items, like chains or additional security locks, if you had them on your old jamb.
Now, your new door jamb is in place, and your locks are working properly. The door should operate like it was meant to and once again provides the security you need to feel comfortable in your home.