How to Replace a Door Jamb

When I got up this morning, and looked over my huge TADID list, this project was not to be found, however I came across the part I needed and was in a spry mood and after living with the eyesore in the kitchen for 4 years I’d had enough.

When we bought this house, the previous owner was an excrement handyman.  Maybe it is more that he did work that he was willing to live with, but I’m not willing to live with it.  At some point he broke down the door from the garage to the interior of the house. My neighbor said he probably did it by pulling the car in too far, but who knows. It must have beens something along those lines because the door jamb had been broken in two and he just kinda stapled it back together.

You might ask, “you lived with this broken door for 4 years, what about security?” well… if someone has gotten into your garage, the flimsy quarter-inch of wood in the door jamb won’t stop someone from getting in the rest of the house if they want. Besides, that’s what security systems and guns are for.

Anyway, so I went ahead and replaced the door jamb and figured I’d document the process. Sadly I never took the before picture, but trust that it was pretty terrible.

Tools you will need for this project:

Razor knife: To cut caulking already on the old door jamb to prevent tearout of paint and drywall when removing. You don’t need anything this fancy unless you just want to look like a badass and spend more on replacement blades.

Pryboy (prybar): To pull off the old moulding and door jamb.

Whacker (Hammer): To whack the pryboy.

Smacker (Rubber mallet): To persuade the old door jamb out of its comfy home, and to coax the new door jamb to nestle in the newly vacated cozy nook. I’m linking a white mallet instead of the black one I actually have. You can see some black rubber scuff marks on the wall of the final pictures of this project and understand why there’s a discrepancy. I’m going to have to hit those black spots when I repaint that wall.

Medium-heavy duty caulk gun: Honestly, you don’t need a heavy duty one, but just don’t waste your money on one of the cheapy ones. If you go with the light duty cheap ones you’re just renting it. You’ll end up having to get a new one by the next project or two you use it on. Having too heavy duty of a caulking gun actually turned a bit disastrous for me in this project… more on this later.

Japanese pull saw : This is by far one of my favorite tools. Mine is Irwin brand but they don’t seem to be available but the one I linked is exactly the same. Pull saws cut on the back stroke, which makes it easier to control for fine details. The best things about this model saw is that the blades are super thin which allows them to be bent for flush cuts or using as an undercut saw for installing flooring, and they have small kerf. This type also has two cutting sides, the finer toothed side is for crosscutting (cutting across the grain of the wood) and the other side has larger teeth for ripping (cutting with the grain).  It is so versatile and efficient that I use it for literally all hand sawn parts in my projects. I can’t recommend it enough.

Shootey boy (nail gun), air straw (air hose), and flat metal balloon (pancake compressor) It also helps to have a thousand or so 1-1/2″ brad nails. You certainly won’t need 1,000 nails, or 1-1/2″ long ones but that’s just how they sell them. They are cheap though so no big deal and the length is good for general use on other projects such as replacing a floor (baseboard and show moulding) and general woodworkery.

Drill boy: Corded drills have more power for the price and to drive the 3″ long screws we’ll be using you’ll need a good bit of oomph. If you have a high voltage lithium cordless drill, use that by all means king DIY.

Cutteyboy: Some kind of jigsaw or vibrating saw to cut the holes and reliefs for the striker plates. See what I used below for a laugh.

3″ construction screws: Just to screw with the next guy who has to fix the door, well use these special-bit screws along with the phillips heads that come with the lock plates.

Optional screw extractor kit: This could be a lifesaver and certainly a time saver.

As for parts, you’ll need to physically go to the local big box store and grab a door jamb if they have one.   One of the reasons I hadn’t done this projects years ago was that the local places only sold the whole door pack, not just a single jamb.  I came across it and bought it on the spot. The one I got is by “Door Shop.”  Now we can talk again about security. If you want a bit more security (an attacker would need maybe a few kicks to bring down the door instead of just one) You can get a door jamb reinforcement kit. I’ve had luck with these in my last house where the previous owner had kicked in the door and I was too inexperienced to replace the entire jamb (which again wouldn’t have been any more secure). Another time I had *thought* I locked myself out of the house in my pajamas while doing a deep clean of the cat boxes. I had to break into my garage and kick in the garage door only to find out that the front door wasn’t in fact locked at all.  I fixed the garage door with just a metal reinforcement kit and made damn sure not to walk outside the house for any reason without my keys in my pocket.  These kits use a hefty steel plate on the jamb near the lock as well as on the hinges and work great.  Honestly thought, with those kits the door itself will break before the jambs or hinges do. Doors are typically made of moulded semi-hollow MDF or in the case of most “steel” doors, they are  this shell of metal with a core of foam with wood just at the hinge and knob attachment points.

Anyway, I’m rambling. I got a damn door jamb. you’ll need some moulding too most likely. I needed it because mine was broke before I started working on it, but in the past, I had to buy new moulding because I broke it when i took off the old stuff and couldn’t reuse it.  Don’t be like me and get something that looks “close enough”.  Actually take a piece from the house to the store and match it exactly if you can.

The first step in the project is to score and cut the caulk from the old door jamb. This may be hard to see if it had been painted over, the whole door can look like one single piece of wood. It is in fact just 2 pieces of moulding and the jamb.  The trick to finding where to score is to look at what sits on top of the wallboard.  That plane is basically where the jamb is and anything proud of that is moulding. Score the moulding where it meets the wall pretty deeply with the blade angled so that it goes between the moulding and the wall like what is shown. Then hit it from the other side as well.

Exterior moulding follows the same rules. Just score by the wall and then on the jamb at the connection of the jamb and moulding.  Don’t forget to score the top miter joint of the moulding and bottom of the moulding as well.

Once you’ve got a little space, slide the flat part of the prybar behind the moulding and smack it with the whacker (hammer) to push it deeper. Once in about 1 to 1.5 inches, pry a bit to loosen the brads that hold the moulding on. Be careful on wall board not to pry so much you crush the gypsum.

Do this for both sides of the door and gently rip the moulding off completely. You’ll likely break one of these, so I just buy a 7-foot section of door casement while I’m at the store.

Remove any screws in the old door jamb.  Luckily, the previous owner chose random length screws ( like he found them in the trash or something, no two were alike) and they were all stripped out. I say “luckily” because I found out that if you strip a phillips head screw enough it can sometimes become a square head screw. Chuck one of those in the old drill and pull the screws out. If they are too stripped for this, use your screw extractor kit.

Once you remove all the screws (did you take off the striker plate for the lock and deadbolt?  or the door hinges if you’re working on that side? Score the bottom caulk where the door jamb meets the threshold sill. Then use a combination of the prybar to pull the jamb away from the wall joist and the smacker (rubber mallet) to nudge the jamb out of the way.

Once that’s done you can measure the two key lengths of the jamb. The total length and then the length of the relief for the jamb cut on both ends (so it could be either thehinge or the lock side) so make doubly– triply sure that you are cutting the correct side and cross cut the total length you measured from the original jamb. Line up the two jambs with the bottoms level with each other and transfer the measurements from the old one onto the new one.

Note the use of the finer teeth on the saw when cross cutting. This gives you a cleaner cut instead of tearing the wood fibers.

Then you can cut the relief.  Even though this is technically ripping the board to a degree, I’m using the finer teeth of the saw for a cleaner finish on the cut.

Then squeeze this top part into the door frame and use the smacker to nudge the bottom in alignment. Note that the bottom of the old jamb might have been supercaulked, so be sure to clean it out first should you need to. Super important! Stand outside and close the door to make sure the weather stripping engages… otherwise you’re going to have a bad time like I did.  If you can see light in the crack between the door and the jamb, then smack it a couple more times to seat it well before moving to the next step!

Once this is in place, it should seat tightly at the top. use your fingers to pull back the weatherstripping and add a few 3″ screws so that when the weatherstripping is back in place it hides the screw heads.

You can now cut the recesses for the lock strikers for the handle and deadbolt. The deadbolt is easiest because its a simple hole with no recess. For measurements, just close the door and mark with a pen where the actual bolt touches.

The next step is to cut the square hole. For this I used a combination of a drill hole and a junior-engineering-design-project add-on for my dremel that turns it into a jigsaw. You can do it a variety of ways however. I honestly recommend a vibration saw with a modified blade. I’d probably just cut the blade smaller with a hacksaw so it would be the right size.

After you’ve sawn the hole for the deadbolt, center your striker plate and drill in the screws and drill Just have mercy on the little guy in the wall…

The striker for the door handle is trickier because it is actually embedded into the frame. They sell nice little router templates for this kind of thing but honestly, you can cut it just about any way you see fit. It doesn’t have to look all that pretty either since the metal will cover up and Freddy Kreuger-faced destruction to the wood. Just make sure not to go too deep or too big.  I used the dremel with the router height adjustment base, but you can just use a sharp chisel if that’s all you got handy.

Once the strikers are in place, you need to put the casement back on the edges. This meets the wall on either side of the door. In my case, I had carefully removed my casement from the exterior part of the door (which is usually thicker and hardier than interior ones), but the interior needed replacing. Just go ahead and grab a 7-foot interior casement moulding at the home store when you buy the jamb because you’ll likely break the interior ones as they are pretty flimsy.

Cut your door casing pieces to length and miter (cut the ) end at 45 degrees to match the top moulding piece. You could measure this but just buy a miter box and save yourself some trouble.  Pull out the shootey boy (nail gun)and tack it with a handful of brads up the length. I always start tacking it at the top so the miter aligns best.

When done with both sides of the moulding, you can need to caulk the cracks on either side of each piece of moulding as well as the top. Now most people drag the caulk gun and deposit the caulk in a trailing fashion, but this is all wrong. Doing it this way leads to globs of caulk in places that need to be smoothed out (usually with your finger, which is also the wrong thing to do…). But worse, it causes weak caulking joints. You only get a thin skin of caulk over the crack you’re trying to fill which doesn’t insulate or hold up well over time.

The correct way to use caulk is to shoot it in front of the caulk gun and move in the direction you are firing it. This crams the caulk into the crack you’re trying to fill as well as leaving a nice finish. You can clean up any remainder with a damp paper towel. (Don’t use your fingers unless you wear a glove. You might think “it’s just caulk” but there’s a lot of nasty chemicals in home supplies that can cause all sorts of organ dysfunctions. Be safe and just use a glove or finger condom.) Check the video below to see the correct way to caulk.

Note: I’ve dun goofed a couple times in the video. First, I’m using clear caulk which when dried looks like someone wiped snot all over the door. I had to go back and sand it all off the exterior and wall and redo it with the right stuff. I should be using this brand or preferably this white caulk. Secondly, you can see the tube is all taped up with white duct tape.  With my vigor in finishing the job, I poked only one pinhole in the tip of the caulk tube after slicing the tip. This led to my new heavy-duty caulk gun putting too much pressure too quickly on the tube.  the tube itself split about 1.5 inches on the top facing me and spurted goo all over the place. This is why you should always wear safety goggles… also keep your mouth closed when you’re doing stuff like this.

 

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