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How to Fit an External Door - A Step by Step Guide

How to Fit an External Door - A Step by Step Guide

Installing a new door to replace your existing external door is similar to fitting an internal door. Yet, you need to consider a few points prior to beginning your front door installation, such as locks and security and weatherproofing.

Replacing your external door is not a very challenging task to accomplish if you have the right tools at hand and just a hint of patience. By following the steps below, you can learn how to fit a front door like a pro.

How To Fit An External Door


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Required Tools And Equipment

  1. Sharp Pencil

  2. Tape Measure

  3. Hardpoint Hand Saw

  4. Drill (Wired or Cordless)

  5. Hammer Or Wooden Mallet

  6. Chisel

  7. Hinges and Screws

  8. Screwdriver

  9. Wooden Wedges

  10. Workbench

  11. Wood Plane (Hand or Power)

  12. Drill Bit Set

  13. Combination Square

  14. Safety Goggles and Eye Protectors

  15. Mask and Mouth Protector

Step 1: Decide Whether To Replace The Door Slab Or Both The Door And Frame

Your first step is to decide whether you need to replace only the existing door slab or both the door and the frame. If your intention is to replace the whole door setup, keep in mind that replacing an external door frame is regarded as controlled fitting under Building Regulations.

This means you will have to keep Building Control notified about your plans if you do not intend to take the help of a professional to carry out this task. Place an application along with the required fee to Building Control for inspection of your work.

Step 2: Measure Door Opening

Getting the accurate measurements of your door frame is crucial if you are planning to fit a new door into an existing frame. Also, you have to measure your existing door to know the perfect fit for its replacement.

Measure Door Opening

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Remember to measure the door height with a tape measure from two different points (left and right) and the width from three points (top, middle, and bottom) to make sure that your dimensions are correct.

Once the measurements are taken, remove your existing door and the door frame too if you are replacing it. Begin by loosening the hinges of the door with a screwdriver and lift it out from the frame. Then look for any external door frame fixings and remove them as well before finally pulling the frame.

Step 3: Mark Up Alterations

Determine if your new door needs a bit of modification or trimming and mark it up appropriately using a sharp pencil. If the alteration to be done is relatively small, then the hanging edge is the best place to carry out the trimming. This way, your external door will suffer the least disruption.

Mark up Alterations

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However, if you need to make larger alterations in the door size, then trimming equally from both sides is what you need to do.

If you are not comfortable making the alterations, an easy solution is to buy a door that comes hung within the frame. This can help in reducing installation issues related to fitting an external door.

Step 4: Trim Door To Size

After you have marked up the alterations to be made, you need to trim your door so that it fits your external door lining. Remember that a well-fitted door should ideally have a gap of 2mm around both sides and the top. The gap below the door will depend on your floor type and/or the carpet thickness.

Trim Door to Size

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To trim the door to size, you will need to use a workbench and hacksaw or a suitable alternate tool. When you have to make small adjustments, a sharp plane will be an appropriate tool to use. While trimming, make sure to work evenly and avoid splintering in the areas that join components.

Step 5: Add The Hinges

Fitting door hinges is one of the most crucial steps in the entire procedure of installing a new door. You will need to fit three hinges to support an external door as such doors are generally heavier in comparison to internal doors. The hinges on an exterior door need to be placed between 5 to 6 inches from the door's top and 7 to 9 inches from its bottom.

Begin by marking out the spots where the hinges will be fixed on your door. Then cut out these recesses using a sharp chisel and hammer and use your drill to screw in the hinges. Ensure that your hinges are flush to the door, and there remains no gap anywhere.

Add the Hinges

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This is also the time to fit your new door frame if you wish to replace it.

Once you have fixed the hinges to the door, now it's time to do the same for the frame. Place your door against the frame to mark out the spots where you need to attach the hinges corresponding to the door. Then repeat the process of chiseling away the extra wood to make space for the hinge plate.

Step 6: Hang The External Door

Now it's time to mount your door in the frame and check the fitting. Make use of wooden wedges to support the door while fixing hinge plates to the frame. As such, you will be able to ensure the correct gap is maintained at the bottom.

Hang the External Door

Affix all the three hinge plates in the door frame using just one screw for each (center screw). Stop and check if the door opens and closes smoothly. If it swings correctly, then drill in the remaining screws to finish your door fixing.

If not, then unscrew from the frame and make the needed adjustments for correct fitting.

The setting of your external door needs to be accurate so that you can secure it with functioning locks. You also need the door to be fitted precisely to minimize weatherproofing issues.

Step 7: Fix Door Handle And Locks

With the door fitted into its position, it's time to fix the handle and the locks. You can find several types of locks in the market, including rim locks, mortice locks, and even locking systems that function at multiple points.

Whichever lock you select, you need to follow the instructions provided by the manufacturer about how to fit it.

Fix Door Handle and Locks

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This process is the same for a door handle or knob. The common handle types for an external door include lever handles and doorknobs. Once you have decided which kind of handle to fix to your door, you can follow the instructions for installing the same.

Remember that your external lock must conform to the British Standards and the specified standards of your insurance policy. If not, your security may be compromised, and your insurance policy may become invalid.

Step 8: Fit External Accessories

The last step of how to fit an external door frame is to learn about positioning external accessories to your door. You need to add a weather-proof membrane to protect the sill, corners, top, and bottom of the opening from the impact of moisture.

After you have put the frame in place, seal every gap using silicone caulking to weatherproof your exterior door. This will prevent moisture from penetrating your door while preventing heat loss from your home.


Now that you have perfectly executed the task of fitting an external door, it is time to run a check and ensure that everything is working fine.

Take the time to check every little detail, including whether the hinges are working properly, if the door lock is functioning perfectly, and if the weatherproofing has been done correctly. Once you cover all these bases, your front door installation is done.

A criminally underrated aspect of fitting a door by yourself is safety. The tools that you need to use for fitting an external door can cause injuries. For the same reason, it's essential to use safety goggles, mask, and gloves while using them.

Once you've taken the necessary precautions, you're all set to take on the task of fitting your door!


Author: Shabana kauser

Shabana Kauser, the Director of Emerald Doors, brings over 20 years of invaluable expertise in the door industry. Her visionary leadership has steered the company to new heights, offering an extensive range of internal and external doors while prioritizing quality and customer satisfaction. The website's glowing reviews stand as a testament to her commitment to excellence. To learn more about Emerald Doors, connect with us on Instagram, Facebook, Twitter, and Pinterest.