Taking accurate measurements for a door threshold requires a more detail than just the length of the opening. Measuring improperly can cause problems with the way the door fits later on. Here’s how you can get accurate measurements for your new door threshold.
Measure the Length
The first step is to get the basic measurement of length. Open the door and get the measurement from one side of the doorjamb to the other. Get an accurate number for the space between the door frame.
Measure the Height
This can be the tricky part. You will need to remove the old threshold before measuring the height. Carefully measure the space from the floor to the bottom of the door. If you are replacing the floor, you will need to take an accurate account of the distance the new floor will leave. If this number is off, even by the slightest amount, it will cause the door to drag on the threshold as it opens and closes. Not only is this annoying, it can damage the door.
If you plan to use weatherstripping you will have to take this into account in your measurements as well. Even a thin layer of caulk can cause the threshold to rise slightly, which will affect the clearance. You will want to plan for all contingencies with the measurements to get an accurate fit.