How to Repair a Door Threshold

An important part of every door in your house is the piece called the “threshold”. The threshold is the solid bottom piece that reinforces the frame. It also helps to keep crawling insects, as well as rain and snow, from entering your home at the bottom of the door.

The final step, if you’ve recently installed a new door frame anywhere in your home, is to place the threshold in. Or, if any of the existing thresholds in your doorways have become rotted or bent out of shape, then you need to replace them.

In order to repair a threshold, you’ll need a replacement piece. It can be either made of wood or aluminum. If you choose to use a wood one, a threshold made of a hardwood should hold up well under normal conditions. It will resist rotting and decay, especially if the door is an exterior one.
You can find replacement thresholds at your local hardware or home supply store.

You’ll also need safety glasses, a measuring tape, an electric drill, assorted drill bits, a saber saw with blades that are suitable for cutting wood, and maybe metal, a pencil, a tube of weatherproof caulking, and a vacuum cleaner with a hose and an attachment.

You’ll need to first remove the existing threshold from the bottom of the door frame. If it’s screwed on, simply remove the screws. If it’s nailed down, then you’ll need to use a claw hammer or a small pry bar to remove the nails. Remove the existing threshold and clean the area underneath with the vacuum hose and attachment.

Next, you’ll need to measure the inside of the door frame. This is the length that the replacement threshold will need to be. The replacement will need to fit snugly in between the sides of the door frame. (It will also need to be set low enough so the door can swing freely. We’ll learn more about that later, though.) Measure the replacement and mark it with a pencil, if you need to trim it off.

If you need to trim the threshold to fit, be sure to protect your eyes with a pair of safety glasses first, Then, use the saber saw with the proper blade to do this. If you are using an aluminum threshold, you may need to gently file any rough edges down with a metal file.

The next step is to dry fit the piece in the doorway. Again, it should fit snugly, but not too tight.
If the threshold has holes predrilled in it, you can skip this next step. Otherwise, you’ll need to use the electric drill and a small bit to drill four or five holes through the top of the wood. You should measure and mark where the holes are going to be located before you drill so they will be spaced evenly apart.

Before you install the replacement threshold, you’ll need to use a weatherproof caulking to create a tight weatherseal underneath the threshold. You’ll need to use the caulking whether the replacement piece is made of wood or aluminum. Follow the manufacturer’s directions on the caulking tube in order to achieve the best results.

Now, place the wood or aluminum threshold into place in between the sides of the door frame.
Press it down; but, before you secure it permanently into place, close the door and then open it to make sure the bottom of the door clears the threshold. It really should with no problem, but it’s best to check first.

Finally, secure the threshold into place by inserting screws into the holes on its topside. Or, you may want to use long nails. Then, use some more of the weatherproof caulking to seal the edges of the wood or aluminum piece.