Last Updated on July 2, 2023 by Stewart

Trimming a door is often needed when new flooring is being installed, and the height of the new flooring means that the bottom of the door would end up snagging on it.

Determine How Much Needs To Be Removed

Before trimming anything, you need to make sure just how much material needs to be removed. Generally speaking, when I’m trimming the bottom of a door, I like to leave around 2-3mm of clearance from the bottom of the door and the top of the flooring. The reason for this is that if the flooring gets changed in the future, and it might sit lower than the one currently being installed, it will end up in a larger gap being present than what you might want.

It can be tough sometimes to figure out how much to take off when previously flooring is already in place. Where possible, remove the old flooring and get samples of the new flooring and see where this marries up to the bottom of the door. Then, add 2-3mm  and make a mark on one side of the door. You should also repeat this at the other side of the door as well by taking the flooring samples and again seeing how it stacks up against the door. When I was planing my doors, I found that they were quite different from the left to the right side. Repeat this process on the other face of the door.

Preparing For The Trim

The next step is to remove the door and secure it to a workbench. Once it’s flat on the bench, take a straight edge, or spirit level and join up the two markings on each side of the door that you’ve previously made. Repeat this process for the other face of the door.

After you’ve made these straight connecting lines, I strongly recommend that you get high quality painters tape and place this above the line that you’ve just made. This will protect the door from splintering. On the painters tape, make an approximate mark that is half of the length of the door into the centre of the door. This is important for later.

Using The Correct Tool

Before using any tools, make sure that you have safety goggles. The sawdust can be very nasty if you get it in your eye, which is the last thing anyone wants.

There are a lot of videos online on what tool to use; an electric planer or a circular saw. Personally I prefer using an electric planer. The reason for this is that they are much safer for the user, and you can also take your time when doing it. They are also much more DIY friendly, and a lot more cost effective as well. I have made a list of the best electric planers, and they can be found, The Best Electric Planers 2023here.

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When using a planer on a new door, I always like to start on the lowest cut possible. This is to make sure that any inconsistencies in the bottom of the door can be easily levelled out before using a deeper cut on the planer.

Planing/Trimming The Door

Now that the door is fully prepped and safely secured on the work bench, it is now time to start to trim it. My strong recommendation is that you work from the outside of the door to the middle and stop at the line mentioned above. The reason for this is that you will have a much lower chance of splintering the bottom of the door when you get to the other end. Once you have trimmed enough from the left to the centre of the door, move to the right to the centre to finish the job off.

It will take slightly longer doing it this way, but from personal experience, it is a much safer option to both yourself and also the door.

Depending on the maximum cutting height of the planer, and also your confidence level, this can be done in a relatively short space of time.

Protecting The Door

After the bottom of the door has been trimmed, it is highly recommended that the bottom of the door is painted, especially if it is a bathroom door. The reason for this is that it will prevent moisture seeping into the door and cause premature warping to it.  By taking a few extra minutes at the end of the trimming, you’ll ensure that the door is protected for years to come.