How to Replace a Door Threshold Extension

What You'll Need
Finishing nails
Caulking gun
Tape measure
Threshold extension
Nail set
Wood dough
Stain and/or water repellent (optional)
If you need to replace your door threshold extension, the material it is made of will determine how you will do the replacement. You will need to do this work before you will be able to do any type of weatherizing of the door. Follow the steps below to cut down on heating and cooling costs. 

      Step 1 - Check for Clearance

      Check any clearance for things like the door trim and the door stop. You may have to remove these things until you are done with the job. Next, open the door as far as you can. After you have done that, use a pry bar and a wedge to pry off the trim without causing any structural damage to the doorway.

      Step 2 - Remove the Old Threshold 

      If you have a circular saw or a chisel, use it to remove the threshold extension from the doorway altogether. Be careful not to damage any part of the floor or other trimming.

      Step 3 - Measure and Cut

      Measure the wooden threshold to the exact size that you need for it to be, and then cut it with a saw. It needs to fit snugly in position for the door to open and close properly. Notch the new threshold so that it fits very securely where the door stops are.

      Step 4 - Clean Up Old Debris

      Clean up any debris left behind from the removal of the old threshold. Residual debris will damage the new threshold extension that you are trying to install.

      Step 4 - Install the Door Threshold

      Distribute a layer of caulk on the bottom where the threshold will be installed. This will ensure that there are no gaps between the floor and its threshold. Gently install the threshold by tapping it with your hammer.

      Drill a few pilot holes that are a little smaller than the finishing nails you will need to use to secure the threshold. Countersink your nails with a nail set. Put the wood dough where the nails are. Let dry and once dried sand lightly with sandpaper.

      Step 5 - Finishing Touches

      If you are using a stain and/or water repellent, apply it once the threshold has dried and been sanded.

        For an Aluminum Threshold

        This is done exactly the same way except for a few differences because of the type of material. You will need a hack saw with fine teeth to cut the threshold down to size. Use a metal file to smooth out all the roughness. Take a drill and drill the screw holes in the threshold. Tighten the screws into the threshold and floor.