The M-D 43346 Premium Rubber door seal presses into an existing kerf channel around the top and sides of a door. M-D lists an 81-inch variant and describes the seal as remaining flexible from -40°F to 140°F. It is not a bottom sweep and cannot correct a misaligned door.
This recommendation uses M-D’s product specifications. It does not claim measured energy savings for a particular house.
Confirm the kerf and leak location
Open the door and inspect the stop for the narrow slot that accepts a kerf tail. Remove a short section of the old seal and compare the channel and insertion profile with M-D’s product diagram. If the jamb has no kerf, choose a documented adhesive or screw-on system instead of forcing this seal into place.
Check for light or air at the head and both jambs. A gap only under the door requires a threshold, sweep or under-door seal matched to that condition. Water entering through flashing or a rotten sill is a building repair, not a weatherstrip problem.
Correct alignment before replacing the seal
Tighten loose hinge screws and check that the latch draws the door evenly against the stop. A sagging or warped door creates different compression from top to bottom and can destroy a new seal or make the door difficult to close.
Measure each side and the head separately. Select the required length and color variant, cut only as the manufacturer directs, and avoid stretching the rubber during installation because it can retract and leave corner gaps.
Check operation after installation
Close and latch the door several times. The seal should make continuous contact without requiring excessive force. Inspect the corners and verify that the latch, deadbolt and emergency egress still operate normally.
Buying decision
Choose M-D 43346 for a compatible kerfed jamb with top-and-side leakage and sound door alignment. Choose another profile for a non-kerfed frame, bottom gap or unusually large/inconsistent clearance.
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Primary source: M-D 43346 Premium Rubber kerf door seal .