Exterior door frames are made up of four main parts: the two vertical sides are known as jambs; the upper horizontal frame above the door is known as the header; and the sill plate at the bottom of the frame is known as the threshold. Thresholds keep weather from penetrating under the door. Minor repairs can be made to thresholds that have not been too worn. Worn thresholds require replacement.
Lift the rubber gasket weather seal along the edge of your threshold from one end and slip it out of the channel that holds it in place. If the seal is the issue, replace the gasket with a rubber threshold gasket and fit it into the channel. If the threshold is loose, proceed.
Inspect the top of the threshold for adjustment screws. They will be brass, with heads near the surface, between the mounting screws, which are recessed deep into the threshold. Adjust the screws counterclockwise to raise the top of the threshold and clockwise to lower it.
Tighten the threshold by tightening the mounting screws in the threshold with a screwdriver if the bottom is raised or if the threshold appears loose. Replace the threshold gasket in the top channel.
Remove the mounting screws and lift the threshold with a pry bar to remove it from the door frame.
Position the old threshold on top of its replacement and trace the ends of the original onto the threshold with a permanent marker.
Fit the new threshold into the door frame and tap it down to the floor. Drive treated deck screws down through the mounting screw holes in the threshold. Adjust the height adjustment screws to raise or lower the top of the threshold to fit the bottom of your door.
Cut the gasket for the new threshold with tin snips to fit the threshold. Fit the threshold gasket into the channel along the top of the threshold.
Things You'll Need:
- Pry bar
- Replacement threshold
- Power cutting tool
- Drill treated deck screws
- “Replacing and Installing Doors and Windows”; T Jeff Williams; 1987
- “Windows and Doors: Installing, Repairing, Replacing”; Taunton Books; 2006
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