If you are adding a new carpet or flooring to a room, then you may need to shorten your wooden interior door. A thicker carpet can prevent doors from swinging as easily as they should, and rather than waiting for the fabric to settle, you might choose instead to trim the bottom off of your door. How well this works will depend upon the type of door that you have. For example, a hollow-core wooden interior door might be more difficult, as you need to limit the amount of wood you remove from the door, as the inside portions will be hollow. Cutting into this area can leave your door unstable.
Step 1 - Measure the Door
Before you begin to cut, you need to work out how much of the area you wish to remove. Start by measuring the contact area between the carpet and the door using a tape measure or ruler. This should tell you how much you need to remove from the bottom of the door. Measure out the area of the door that needs to be removed, creating a parallel line across the door.
You should then use your chalk to mark this out clearly. Measure again to make sure that this is less than an inch in height, although you will find that you only need to remove a fraction of this to allow the wooden interior door to slide over the carpet.
Step 2 - Prepare the Door
Put on your safety glasses before you make any holes in the door. Start making your cut by taking your knife all along the mark you have made on the wooden door. This should be thick enough so that you can place the blade of your saw firmly into the slot. Put a line of tape above this cut in order to prevent the remaining part of the door from splintering as you start to cut. Once you have finished this cut, take the door from its hinges, and place it over your workbench, or a similar flat surface, so that you can make the cut.
Step 3 - Cut Down the Door
When the door is firmly in place, you can start to cut it down. Hold the door with your free hand, and place the saw into the notch you have made with the utility knife. Start sawing slowly across the door, making sure that you follow the line of the cuts, and being careful not to cut through to the hollow part of the door.
Hold your saw steadily, so that you don't fray the edges of the wooden door, as this can cause marks on the edge of the door. You may also want to use a piece of sandpaper along the finished edge in order to remove small splinters which could catch on the carpet. When you have finished sawing, replace the door into the door frame, and clear away your work tools.