Interior wooden door.

How To Hang A Door

Originally contributed by Tim Pierce • last updated 4/9/2021

40 minsPrep Time
10 minsActive Time
IntermediateDifficulty
40 minsPrep Time
10 minsActive Time
IntermediateDifficulty

Sometimes inside doors simply need to be replaced.

Whether it’s because they’re no longer functional or don’t match your updated decor, hanging a new interior door can open your space to new possibilities.

DIY interior door replacement can involve pre-hung doors (doors that are already prepped for hinges and hardware) and slab doors that are more like blank canvases.

We’ll show you how to install an interior door that is not pre-hung, teaching you everything: how to take an old door off its hinges, how to cut hinge gains into a slab door, installing door hinges, prepping for hardware, creating a bevel, and eventually how to hang a new door.

Oh, and we’ll demonstrate the easiest method to achieve a new slab door installation that involves the fewest number of specialized tools!

Follow our DIY how-to guide and learn how to hang an interior slab door in an existing frame by matching the hinge gains, latch and handle setup from the previous door!

Let's Make It

Equipment

  • Pencil
  • Tape measure
  • Speed square/ rafter square
  • Utility knife
  • Center punch
  • Hammer
  • Wood chisel
  • Screwdriver
  • Drill
  • Spade drill bit
  • Hole saw drill bit
  • Orbital sander
  • Router (optional)
  • Butt hinge marker (optional)
  • Door lock installation kit (optional)
  • Power plane/ block plane (optional)

Materials

  • Slab door
  • Door hinges (can be taken from existing door)
  • Wood screws (at least 1")
01/7

Remove The Old Door

How To Take Door Off Hinges

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If you’re swapping an existing door for a new one, the first step in the DIY interior door replacement and installation process is to remove the old one. Makes sense, right?

Use a drill or screwdriver to unfasten the screws connecting the existing door to the interior door frame.

Remove the hinges from the interior door frame, but leave the hinges connected to the door for now.

Tip: Mark the top of the old door with a pencil or tape, as the old door’s orientation is crucial in the preparation and eventually the installation of the new interior slab door.


No one wants to get through all of these steps only to realize the door is upside down.

02/7

Remove Hardware

How To Remove Door Hardware

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There are many different types of interior door hardware out there, so we’ve compiled a separate lesson detailing how to remove various knobs and handles.

However, if your door hardware is a simple setup with exposed screws, merely unfasten the screws with a screwdriver or drill to remove the knob/handle.

Pull the handles away from the face of the door. The locking mechanism will then be able to be removed from the side.

How To Remove Door Hinges

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When installing new inside doors into an existing interior door frame, it’s a good idea to reuse the old hinges if they are in good working order. The frame is already prepared to house them and will make the transition easier.

If not, match the size of the old hinges to fit the interior door frame.

Use a drill or screwdriver to remove the door hinges.

03/7

Prep New Slab Door

How To Clamp Inside Doors Together

Using a trigger clamp (also known as a quick grip, quick action clamp, or spreader clamp), clamp the old door to the new door as tightly as possible, so they don't move around.

Ensure the doors are flush at the top. See, marking out which end is up in the first step paid off already!

Even if the doors are slightly different heights (which is the case in our example), it’s much better to leave a slightly larger gap at the bottom of the interior door than the top.

Face the hinge side of the old door upwards, and make sure the new door is even to the other door on this side, as well. This side is where we’ll be installing the new interior door hinges. 

Mark Hinge Placement

With the doors firmly together, use a pencil and speed square (rafter square) to mark the locations of the new interior door hinges by lining them up with the hinge gains (insets) on the old door.

Measure the distance between the top of the hinge gain and the door and transfer this measurement onto the new door to determine the placement of the new hinges.

Properly installing door hinges will make sure the door moves easily through the frame.

Fasten Middle Screw On Hinges

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Using your markings, line up the hinge on the new door.

With a center punch and a hammer, make an impression in the center of the middle hole on the hinge (often they have three holes)

The center punch impression acts as a guide and ensures the screw will be fastened straight.

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Use a drill to fasten the middle screw of the hinge into the new door.

Only screw in the middle screw. It’s important not to attach the other screws quite yet!

Square Hinges

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By pressing the bottom plate of the hinge against the door, it will naturally square the hinge to the door.

Only having the middle screw in place allows the hinge to rotate slightly from side to side until it is square with the interior door.

Once the bottom plate of the hinge is flush with the door, the hinge is square.

When installing hinges on inside doors, it is imperative that the hinges are square to allow for ease of movement.

Attach Hinge For Template

Repeat the process initially used to attach the center screw of the hinge until all the hinges are fully installed.

First, center punch the remaining holes in the hinges in preparation for fastening the hinges into place with screws.

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Finish off the screws by installing them in the hinge with a drill.

The hinges will be protruding from the door, unlike how they were seated on the old door.

The reason for attaching the hinges like now is to use them as a template to cut the door hinges.

The hinges will eventually have to be detached and reattached to the door, but this method requires the fewest specialized tools, and your holes will be pre-drilled for the final hinge installation.

Now let’s get into how to cut insets for the door hinges, also known as making hinge gains.

04/7

Installing Door Hinges

How To Cut Door Hinges

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Use a utility knife to score the wood around the edges of the hinges.

Try to cut down into the wood roughly the depth of the hinges.

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Tip: If the hinges have rounded corners, use the utility knife’s tip and poke multiple times down into the wood until you get a well-perforated line. 

Info: If you have a lot of slab doors that need to have gains cut into them, ask your local hardware store about acquiring a butt hinge marker or gauge, as this can make the process quicker and easier. 


Find a marker that matches the hinges you’re working with, and hit the butt hinge marker with a hammer. The marker will leave a depression (score lines) in the wood at the desired depth.


Our method is based on demonstrating the easiest way with the fewest number of tools.

Create Hinge Gains (Two Methods)

Using A Hand Chisel

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The goal with each of these methods (hand chisel and router) is to remove the wood inside the scored lines at a particular depth.

When installing door hinges, the interior door hinge needs to sit flush against the door.

Start by holding the wood chisel at the 90-degree angle and gently tap it with a hammer, going over the previously scored lines.

Face the flat side of the chisel towards the wood on the door that will not need to be cut out.

Be careful not to cut deeper than the thickness of the hinge.

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Now angle the chisel with the flat side facing up, and slowly chisel out the wood by tapping the handle with a hammer until the wood is removed.

The wood near the score lines should just splinter away as the chisel gets near the line. Take your time in this process until you’ve reached the depth of the hinges.

You can determine if the depth is correct by test fitting the hinges to see whether they sit flush with the side of the door.

Tip: The sharper the wood chisel, the easier it will be to shave the wood away. It also provides a cleaner cut.

How To Install Door Hinges (Wood Chisel)

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Once the wood is cleared away and nicely cleaned up so that the hinge fits snugly into the newly created hinge gain, use a drill to screw in and reinstall the door hinges using the previously drilled holes.

Using A Router

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For those who have access to a laminate or trim router, this is a speedier, cleaner, and more efficient option than using a wood chisel.

The router will need a flush bit to create a flat door hinge gain.

Start by setting the depth of the router to match the thickness of the hinges.

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With a firm grip on the router and the plate of the router flat against the door, move the bit slowly into the wood of the door to clear away the wood within the scored lines.

Stay slightly away from the lines and carefully work towards them. If the scored lines are deep enough, the wood will splinter away, leaving behind a perfect edge.

How To Install Door Hinges (Router)

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As mentioned earlier during the wood chisel explanation, once the wood is cleared away so that the hinge fits even with the door, use a drill to screw in and reinstall the door hinges using the previously drilled holes.

05/7

Prep Door Replacement For Hardware

Select Bit Sizes

Now that we’ve finished installing the door hinges, it’s time to focus on the hardware.

If using the existing hardware found on the previous door in this DIY interior door installation project, match a spade bit to the side of the existing door, which will hold the latch mechanism.

Also match a hole saw bit with the same diameter as the one found on the face of the door.

If you are installing brand new hardware, follow the manufacturer's installation instructions to determine the size of the drill bits required for the interior door.

Drill Front Hardware Hole

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Line up the existing door with the new door, making sure that the tops of the doors are flush and they are square with one another.

With the old interior door on top, use it as a guide to drill a hole into the new door below with the hole saw.

Tip: If the new door has a glass panel, make sure to support the glass underneath to prevent it from breaking.

Mark Latch Placement

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Using a speed square (rafter square), mark the location of the side hole based on either the existing door or as per the manufacturer’s instructions for new hardware.

Drill Side Hardware Hole

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Stand up the door and use the spade bit to drill a hole through the core of the interior door, connecting it to the hole made with the hole saw on the face.

The replacement interior door is now prepared for hardware installation.

Info: Door lock installation kits are also available to help guide hole placement, but our DIY method teaches you how to install an interior door without this specialized tool.

06/7

Create Bevel On Interior Door Replacement

Unlike prehung doors, slab doors don’t come with a pre-fabricated bevel.

A micro bevel (slight angle) is always added to interior doors so that when they close, the edge of the door doesn’t bump against the frame/ door jamb when in the closed position.

This allows the door to be functional while being tight in the frame, making the gap as small as possible.

When hanging interior doors, it’s essential to establish this bevel to keep the gaps in the interior door replacement tight.

Mark Line For Bevel

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Mark a line about an eighth of an inch on the face of the stop side of the door. The stop side is the side of the door that will be against the jamb when the door is closed.

There are several methods used to create a bevel, but we’ll show you how to make one using an orbital sander because it is a more common tool.

Info: Other tools typically used to create this bevel are a power plane or a block plane. While using a plane is easier and more efficient, it is a specialized tool, and if you haven’t been able to tell already, we’re trying to avoid those this time around.

Create Bevel (Using A Sander)

Apply a lot of pressure and run the sander on an angle back and forth along the door until you reach the line evenly.

Be careful not to sand too much off of the finished edge on the face of the stop side of the door.

The sander should barely take any material away from the open side of the door. Think of it as taking the door’s squared edge and adding a slight tilt, angle or slope to it.

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Try to make the bevel as uniform as possible with the sander, taking time to smooth out any inconsistencies.

Look down the interior door lengthwise to get a better idea of areas that may need further sanding.

The replacement interior slab door is now ready for installation. We’ll now show you how to hang your new interior door inside your home!

07/7

New Interior Door Installation

How To Hang And Install An Interior Door

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All that’s left to do in the DIY interior door replacement and installation project is to attach the newly prepared door to the door frame.

Face the cylindrical part of the hinge (knuckles) toward the side of the door that opens. If the door opens towards the side of the door in which you are standing, make sure the hinge knuckles are on that side of the replacement door.

When hanging an interior door, use a drill to screw the hinges back into place. Check to see that the door moves freely through the frame and whether there are any gaps present.

If the door doesn’t close, a greater bevel may be required. If there are gaps, try slightly readjusting the hinges on the door frame.

Once everything looks good, reinstall the previous hardware, or install the new hardware following the manufacturer’s instructions.

To see a more comprehensive guide to DIY interior door hardware installation, check out our lesson on door hardware.

If you have any tips or tricks you’ve picked up on how to install an interior door, let us know!

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