How to measure and hang a new front door


Croft Triple Glazed Door

In the first part of this series on doors, we looked at how to choose the right front door for your home. In this part we take a look at how to measure your new front door and how to hang it.

A badly fitting door not only lets in draughts, but in some cases can also invalidate your home insurance policy, particularly if you don’t have the right locks. Before undertaking this task check with your insurance provider, and make sure you’re confident carrying out the job.

It’s worth noting that this is a job for a confident DIYer, and that you should always enlist the help of a friend to work with, as doors can be heavy and cumbersome. If you’re in any way unsure about carrying out this task then always seek assistance from a professional. 

Measuring a door
Measuring the door

The first step when it comes to fitting a new door is knowing how to measure the door size. This is quite a crucial step, as measuring incorrectly could lead to a less secure and difficult to use door. Always measure once, then measure again!

We recommend that you measure three times across the width of the door – bottom, middle and top – then three times along the length of the door – left hand side, middle and right hand side. Measure the outside of the door first, from brickwork to brickwork, including the door, frame and the sill (or the very bottom of the door if you don’t have a sill). Take an additional diagonal measurement across both ways of the door, corner to corner (this will confirm that the opening is square).

When choosing a new door, you need to decide whether you want to replace just the door, or the whole frame as well. Replacing the frame at the same time as the door will ensure that you get a nice fit, but isn’t always necessary. If you need some help on choosing a new front door, then take a look at our previous blog.

Remove the old door by unscrewing the hinges and lifting the door from the jamb. If there is a thick layer of paint covering the screws, then use an old chisel to gently scrape this away, or give it a good once over with some turps and an old cloth.

Trimming the new door to size

Once you’ve chosen your lovely new door and are confident that you have the right size, hold the door in the frame to check if it needs any adjustment. A well fitted door should have a 2mm gap at the top and on either side. The gap at the bottom is dependent on the thickness of your carpet or flooring, but 5mm is a ballpark figure. If you have thick carpet then it might be worth investing in rising butt hinges which lifts the door as you open it. 

Trim the new door to size using an electric or hand planer, and ensure a smooth finish by sanding down. When trimming the new door, you should always wear goggles and a face mask when cutting or planning wood. Always trim the door equally from both edges or the top and the bottom, as it may weaken the joints if trimmed by more than 15mm on one side. 

Fixing hinges to a door
Fixing the hinges & hanging the door

Check the fit of your new door by propping the door into the opening, wedged into position at the bottom. Check your hinges fit the door frame, and if not, mark where the new ones will be and chisel away the extra wood so they sit snugly. Fix the new hinges in to the recesses in the door frame using one centre screw, and mark around where the position of the hinges on the new door will be. 

Remove the hinges from the frame and sit them against the door, lining them up with the pencil marks you made, then draw around where the hinge will sit. Start removing the waste wood by chiselling out to the same depth as the hinge flap.

Make starter holes for your screws at the areas marked. Attach your hinges to the door using just one screw and, enlisting the help of a friend to hold the door, again prop the door up and screw into the frame using one screw, and check it opens and closes nicely. Once you’re confident that the door is a good fit, attach the rest of the screws. 

If you’re unsure about fitting the door, take a look at this brilliant video: