Replacing interior doors might seem intimidating, but it’s actually a pretty easy process if you know what you’re doing. The beauty of replacing doors in today’s day and age is that you can buy a pre-hung door, which limits the tools and skills you need to install your door. In this DIY guide, we’ll explain the process of replacing an interior door from start to finish to help you save money in the process of upgrading your living space.
Prepping to Replace an Interior Door
Before you dive in and start ripping out your old door, you need to make sure you purchase a replacement door that will fit inside your wall opening. You can measure from inside jamb to inside jamb to get a rough estimate, but since you’ll be removing your door trim anyway, it’s best to pry the side pieces off carefully with your pry bar to expose the edges of the wall opening.
Measure across the door at the top from the framing on one side of your door to the framing on the other side. Make sure you don’t measure to and from the door frame but rather to the wall framing that surrounds your door frame. Take two additional measurements in the middle and at the bottom of your door, and use the shortest of the three. That’s the width of your rough opening.
Next, pry off the top piece of trim and measure from the floor up to the wall framing above the door. That’s the height of your rough opening, which should be 80 inches for standard doors. Make sure you purchase a pre-hung door that will fit inside your wall opening before you get started.
Angi Tip
Accurate door measurements are essential for a successful installation. Height and width matter, but jamb width, door swing, and clearance are also key. A professional installer can assess these details and recommend the best solutions.
If you haven’t removed the door trim around your interior door already to measure the rough opening, do so now. Slide the pry bar behind the trim and tap it lightly with your hammer. Push the pry bar forward and pull the trim off little by little.
Once removed, set the trim aside for reinstallation later.
Remove the Old Door
Insert your screwdriver into the bottom of the hinges, and gently tap upward with your hammer until you can pull the hinge pins out. It’s a good idea to have someone hold the door while you do this to avoid it falling and potentially damaging your floor.
Once the hinge pins are out, pull the door toward you to remove it.
Remove the Old Door Frame
With the door trim removed, you should be able to see where your old door frame is nailed or screwed into the surrounding wall framing. Use your reciprocating saw to cut all of the nails or screws holding your old frame on.
Once the fasteners are all cut, pull your old door frame pieces out.
Center the New Door
Next, stand up your new pre-hung door in the wall opening. You should have at least 1/4 of an inch of space on each side and the top of the new frame, but you’ll likely have one inch or more. Center your new door frame in the wall opening so that the space on both sides of the frame is about even. You can measure to get it perfectly centered, but this isn’t necessary.
Shim the Door
Shim your door by gently inserting shims between the door jamb and the studs surrounding it to hold it in place. Don’t use force yet to push the shims in. When you insert shims, always install two at a time facing opposite directions. This will provide a perfectly flat surface for your door to rest on rather than a slanted one that will cause warping of the frame over time.
You should place shims in the following locations around your door:
Behind the top hinge
Behind the bottom hinge
Behind the middle hinge (optional)
At the top of the hinge side
At the bottom of the hinge side
At the top of the lock side
At the bottom of the lock side
In the middle of the lock side (optional)
In the middle of the header (optional)
Check That it’s Level and Plumb
Now, hold your small level against the header to make sure it’s level. Adjust the door frame if necessary.
Hold your 6-foot level against the hinges. If the hinges are perfectly plumb, check that the lock side is also plumb by placing the 6-foot level against that jamb. If both are plumb, move on.
It’s more likely that you’ll need to make adjustments. If the top of your hinge side is shifted outward or is too close to the frame around it, gently hammer in one of the shims behind the top hinge. If the bottom side is shifted toward the wall frame, gently hammer in one of the shims behind the bottom hinge to kick it outward.
Always adjust the shims on the hinge side first, as this is the side of the frame that supports the weight of your door. Once that side is perfectly plumb, repeat these steps for the lock side.
Test the Door
With your door temporarily installed, it’s time to test it. Start by swinging the door open and closed manually. You shouldn’t hear any noise, feel any resistance, or notice any other door problems.
If your door frame isn’t plumb, your door will automatically swing open or closed, so test that next. Open your door a quarter of the way and let go. If it moves, you’ll have to make some adjustments. Then, open it halfway and three-quarters of the way and perform the same test.
Attach the New Door
Check again that your door is roughly centered in the wall opening and that both sides are plumb. If they are, you can attach your door frame using 3-inch finish nails or screws. Screws will hold better over time, but finish nails are easier to hide. If you do use screws, it’s a good idea to predrill using a countersink bit.
Using your hammer or finish nailer for nails or your power drill for screws, attach your door frame to the studs in the wall opening in the following places:
Through the shims behind each of your hinges
Through the top shims on both sides
Through the bottom shims on both sides
Through the middle shims on the lock side (optional)
Through the shims in the header (optional)
Reinstall the Trim
You can finish up the project by reinstalling your door trim or installing new trim if you prefer. Line up the inside of the trim with the inside of the door frame. Secure the trim in place with 1-inch finish nails.
You can also replace your door threshold after installing your new door if you want to upgrade your door further.
DIY vs. Hiring a Pro
Replacing an interior door is a relatively simple process, provided you have a standard rough opening and are installing a pre-hung door. If that’s the case, homeowners with even just a little DIY experience should be able to get the job done with a bit of planning and patience.
If you try to do the work yourself and struggle to get your door level and plumb, don’t be afraid to call in a door installer near you for help. Interior door installation costs around $100 to have the work done professionally, but you’re guaranteed to get a good installation that leaves your door fully operational and looking clean and tidy.
Additionally, we recommend hiring a professional if you buy a slab door rather than a pre-hung door. Prepping a slab door for installation is a little more complicated and involves additional tools and experience, so DIYing is more challenging.
Frequently Asked Questions
You can replace a door without replacing the door frame around it if you buy a slab door. Start by removing the hinge pins in your old door, and then pull the door off. Unscrew the hinge plates from the old door, and use them as templates to mark where they go on the new door. Make sure you place them correctly. Use a router to route out a space for the hinges, and then attach them to your new door with screws. Reassemble the hinges, and put the hinge pins back in place.
In most cases, a pre-hung door is a better option, not only because it’s far easier to install as a DIY project, but also because you’ll get a new frame and a new door at the same time for a more complete upgrade. Replacing a door costs more with pre-hung doors, but the additional investment is usually well worth the money. Pre-hung doors require fewer tools and less experience to install properly. With that being said, a slab door might be better if you’re on a tight budget or have a custom wall opening size that a pre-hung door won’t match.
No, you should install your pre-hung door frame with the door attached. The point of a pre-hung door is that you don’t have to worry about hanging your door. Simply place the door in its frame in the center of the wall opening, make sure both sides are plumb, shim the door in place, and screw the new frame into the studs around the wall opening.
Dan is a writer and property manager and can be found sharing his home improvement tips on sites like EcoWatch and Today’s Homeowner. He loves sharing his years of hands-on experience and love of DIY to help homeowners bring their visions to life.
Dan is a writer and property manager and can be found sharing his home improvement tips on sites like EcoWatch and Today’s Homeowner. He loves sharing his years of hands-on experience and love of DIY to help homeowners bring their visions to life.
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