The bottom weatherstrip (or door sweep) on the exterior door was worn out after 8+ years of daily use. I noticed the problem when wind driven rainwater leaked under the door. The weatherstrip needs to be snug against the door threshold for a good seal and it wears out over time when the door is opened and closed.
The new part cost about $9.00 from Home Depot and the repair was performed in about 10 minutes.
How to Replace a Worn Out Door Bottom Weatherstrip
Remove the Exterior Door
With a helper holding the door, I began by removing the door from the hinges by driving out the hinge pins with a screw driver and hammer. I laid the door on its side edgewise to inspect the bottom weatherstrip (see above photo). Be careful – my metal and glass door was heavy, weighing at least 50lbs.
Measure the length and width of the door. My door is 32 inches long and 1-3/4 inches wide.
I took a photo of the worn-out weatherstrip with my iPhone (like the above photo) to compare and match the part when shopping for a replacement at the hardware store.
Door Sweep Replacement Part
The replacement door bottom weatherstrip (a.k.a. doorsweep) that fits my door is a Frost King part # UDS36. I bought it at Home Depot for $8.99.
Remove the Old Door Bottom Weatherstrip
The weatherstrip is attached by barbed ribs that snap into grooves (or kerfs) in the door bottom. To remove the old weatherstrip, just pull it off as shown. I put a coat of oil-based wood preservative on the exposed wood as a waterproofing agent.
Install the New Door Bottom Weatherstrip
My door is 32 inches but the new weatherstrip is 36 inches long. It was necessary to cut 2 inches off both ends (4 inches total) because the barbed ribs are set back from the ends to fit a 36 inch door.
Measured the length of bottom door grove and trim the barbed ribs to fit the door as shown:
The new weatherstrip is checked for the correct length with the door bottom. The door grooves are highlighted by the red lines:
The weatherstrip snaps into the door bottom by the barbed ribs and grooves. The instructions call for a rubber mallet, but it was easy enough to smack it with the palm of my hand for a tight fit against the door bottom.
Note: The “tube and fin” design of the weatherstrip. I’m holding the “tube” between my thumb and finger. The weatherstrip should be installed with the tube side facing the outdoors. The tube acts as a compressible gasket to seal out the weather.
The new weatherstrip installed and ready for use:
Reinstall the door by aligning the door hinges with the hinge leaves, then replace the hinge pins.
The door shuts snugly now and is free of air drafts and water leaks.
I later decided to replace the entire exterior door and door frame with a new energy efficient model having a single pane of glass that’s easy to clean.