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DIY Inspiration - How to Fit a New Door into an Old Frame

Article Topics:

1.     Reasons to Replace and Interior Door

2.     Guide to Fitting a New Door into and Old Frame

3.     Tools and Materials Required

4.     Hanging Your New Door

5.     Fitting the Door Handle

6.     Video Guide


Welcome to another practical and hopefully insightful DIY inspiration article. This time we're going to explore a common DIY task that, with a little knowhow, will give you the satisfaction of a job well done, and save you money. We're going to look at how to fit a new interior door into an old door frame.

Existing frame - pre hung door

First, let's talk about some of the motivations for replacing an old door and the benefits that a new door can bring to a room. Then we'll get into a practical guide of what you will need in terms of tools and hardware, and how to fit your new door into an existing interior door frame.

Reasons to Replace an Interior Door

There are myriad reasons why people choose to replace an interior door with a new one, into an existing door frame. But we can perhaps round them up into the following seven situations where a new door might be desirable.

Door small gaps close-up

Reduced Cost

Perhaps the most common reason for replacing a door into an old door frame is lower cost. The savings are significant if you fit your door yourself, and as door frame replacement cost can be expensive, using the existing one make sense.  

Your Door Looks Tired

If your current interior doors are outdated or no longer match your home's décor, replacing them can give a room or space a fresh, new look. This could include upgrading door furniture and hardware, such as door handles, knobs and hinges, as well as giving your door a fresh lick of paint, or staining natural timber.

Old door - old trim - old backplate

Signs of Wear and Tear

Over time, interior doors can experience wear and tear, including scratches, scuffs, dents, and chipped paint. If these signs of aging are detracting from the appearance of your room, it's a good time to consider replacement. Also, damage to the door itself due to years of consant use and abuse. 

Your Door isn't Working Properly

Doors that don't close properly, suffer rough opening, stick, or don't latch properly can be frustrating to live with. Replacing a poorly performing door and its hardware will solve those problems.

You want a Door that has better Security, Privacy or Noise Reduction

In some cases, doors might not provide adequate security or privacy, especially if they are old or flimsy or are not lockable. Upgrading to a more solid, lockable door will improve room security and enhance your home's overall safety. Mortice locks are most common for home interior doors.

If you're looking to reduce noise crosstalk, choosing a door with better soundproofing qualities will be beneficial.

Helping to Improve Energy Efficiency

Upgrading to thicker doors or better insulated doors can improve the energy efficiency of a room by reducing heat loss. Although in well insulated homes draughts are unlikely to be an issue.

But more traditional, less energy efficient homes could benefit from new, well fitted interior doors. If improved energy efficiency is you goal, then consider choosing a door with foam insulation.

Increasing Natural Light

You might have a room or other space that would benefit from additional natural light. A way to increase the amount of natural light could be to replace an existing timber panel or slab door with a glass panelled door. Although the panels will be glass, if the door frame is timber, the process of fitting into and old door frame remains broadly the same.

It probably goes without say, but a door with glass elements should be handled with care — ideally get a friend of family member to help you.

Your Guide to Fitting a New Door into an Old Frame

Tools and Materials

This step-by-step guide will show you what a DIY door replacement involves without the need to replace a door frame, and how to go about planning and executing your project. 

Ok. Let's kick off by listing a few tools and materials you may need:

- A new interior door (obviously).

- Hinges, handles and other hardware (if not reusing your old door hardware). You can get all you need in a dedicated handle pack or knob pack.

Door in door frame kit - new hinges - latch with latch plate - strike plate


Trestles in workshop

- Trestles or work bench

- G clamps

- Utility square

- Rail saw or circular saw

- Power plane

- Power drill

- Tape measure

Measure tape -

- Wood or rubber wedges, or similar

- Screw driver

- Sharp chisel

- Hammer

- Utility knife

- Pencil

- Spirit level

- Wood filler (if needed)

- Sandpaper

- Safety goggles

- Paint or stain (if needed)

Old, prehung door - natural dark wood - antique brass door knob

Hanging Your New Door

You might have a brand new door. Your door may be upcycled. Or you might want to spruce-up your old door and rehang it with a new handle, latch and hinges. Whichever way you choose, the fitting process will be the same. For the purposes of this guide, we're going to focus on fitting a brand new door.

Step 1 - Your New Door

When you get your new door, it's a good idea to let it lie flat in a room, on trestles ideally, for a few days to become acclimatised to your home: temperature, humidity etc.

Replacement door - interior door in door frame - white

Step 2 - Remove You Old Door

First thing to do is unscrew your old door's hinges and carefully lift the door away from the door frame. It will be easier if you get a helping hand from a friend or family member for safety, and just to make life easier. Once removed, put your old door out of the way.

Step 3 - Mark Up Your Door

  1. Stand your new door in the door frame as it would be if it were closed. Take your pencil and mark clearly on the door where it will fit nicely into the frame. Next, place your door flat and measure the distance from the door's top edge to your pencil line.
  2. Copy this measurement, adding 3mm, to the bottom edge of the door, marking with your pencil — the extra 3mm is to clear carpet or other floor covering, ensuring that your door will swing freely.

Step 4 - Cut to Size

  1. Secure the door flat using your G clamps, on a trestle table or work bench.
  2. With either your plane or your saw (depending how much wood needs to be taken away) carefully remove the excess timber at the bottom of your door to size — remember to wear your safety goggles for this.
  3. Repeat the process of measuring and marking for the sides of your door too, and remove excess wood to size.
  4. Trim surplus wood from both sides of the door to keep it looking even. For example, if you need to take 6mm, divide by two and take 3mm from each side. Remember, whatever your measurement is, add 3mm for side clearance.

Selection of a few tools

Step 5 - Mark Up Hinges

  1. Once your door is cut to size, place it in the existing frame and insert shims or a couple of wedges underneath the door to keep it in place at its functional height.
  2. Ensure that you are using the correct hinges for your door. This guide will help. 
  3. Look to see where the hinges screw into the door frame. With your pencil mark where the hinge recesses in the frame line up with the hinge side door edge.
  4. Mark the outline of the hinges where they will go on the door edge. Then do the same with the thickness of your hinge on the face edge of the door. 

Hinges fixing to door just a door frame - new frame - white

Step 6 - Fit Hinges

  1. Chisel out the hinge recesses in the door to accommodate the hinges. Start with following the hinge outline. Then make small 5mm cuts at 90 degrees. This will help to prevent the wood from splitting. Then from the flat side of the door, chip away at the excess wood.
  2. Hold the hinge in place, and using the hinge screw holes make pilot holes in the door to help prevent splitting when you screw the hinges in place. For a detailed look at fitting internal door hinges check out this article

Step 7 - Hang Your Door

  1. With the hinges fitted, line your door up in the door frame — you might need a hand to do this.
  2. Attach the door to the frame with a single screw in each hinge to secure it.
  3. Double check your door swings correctly. If so screw in the remaining hinge screws.

Now your door's installed, let's move on to fitting your door handle.

White internal door frame and door with modern handles

Fitting Your New Door Handle

Step 1

First, measure the height on your door where you want your handle to go — rule of thumb is 1m or 10% either way.

Step 2

Then measure the width of the latch mechanism and choose a drill bit of the same size. At the height mark on the door edge, drill a hole to accommodate the latch.

Step 3

  1. Insert latch mechanism and hold it in place while marking the latch plate outline on the door edge.
  2. Once marked, remove the latch mechanism and carefully chisel out the depth of the latch plate so that it sits flush with the door edge.

Step 4

Place the latch in position on the door surface and with your pencil mark the door, through the latch spindle hole.

Step 5

  1. Using the same drill bit, drill a hole through the door. Note, don't go all the way through. Stop when the bit tip shows through the other side of the door.
  2. Then drill the rest of the hole from the other side using the tip hole as a guide.

Step 6

  1. Insert the latch mechanism and spindle, place the handles over the top.
  2. Using the handle screw holes, make pilot holes in the door and screw the handle into place.

Step 7

  1. Remove the old strike plate from the door frame and replace it with the new one.
  2. Double check your door is swinging and latching correctly.

Your new door is now ready to use!

Internal door frame -

Video Guide

This video will help guide you through fitting a new door into an existing door frame. 

Final Thoughts

So there you have it. A complete guide to a common DIY project. With the right tools, materials and your choice of handle pack, you can easily transform the doors in your home at a fraction of the cost in just a few hours without a replacement door frame. And remember, the principles of hanging an interior door can apply to an exterior door and old external door frame too.

For a whole world of handle and door knob DIY inspiration, visit Hiatt Hardware.