Fix how the door fits before you buy any seal, then choose the seal by where the air gets in. Gaps at the top and sides call for jamb weatherstrip. A gap at the bottom calls for a sweep, door-bottom shoe or threshold seal. A boxed “door weatherstripping kit” helps only when its parts match the gap you measured and the profile of your jamb and threshold.
Repair the door fit first
Close and latch the door, then inspect the top, the hinge side, the latch side and the threshold. Look for daylight, loose hinges, a latch that does not pull the slab against the stop, a warped slab, damaged stop molding, a worn threshold and water staining.
The U.S. Department of Energy’s installer job aid treats visible daylight and a loose-fitting door as signs of air leakage. It says to adjust loose hinges, knobs, strike plates and the door itself as needed before weatherstripping. A thick foam strip will not fix a sagging or misaligned door, and it can stop the latch from engaging. The strike-plate alignment guide covers the most common latch fix.
Match the seal to the leak
DOE describes weatherstripping as the seal for moving parts, such as a door against its stop. Caulk is for stationary joints, such as the frame against the wall.
| Leak location | Seal class to consider | Check before buying |
|---|---|---|
| Top and side stops | Compression weatherstrip, kerf-in bulb, V-strip or a manufacturer replacement | Existing kerf slot, gap range, closing pressure and finish |
| Bottom of door | Sweep, door-bottom shoe or threshold seal | Door thickness, threshold profile, floor clearance and water path |
| Between frame and rough opening | Air sealing behind the trim | This is a stationary joint, not a weatherstrip job |
| Mail slot or other opening | Purpose-built gasket or replacement part | Fire, security, weather and accessibility requirements |
If the jamb already has a kerf slot, a press-in kerf seal such as the M-D 43346 fits that existing slot. Jambs without a slot need an adhesive or screw-on system. Weatherstrip should compress enough to seal without making you slam the door. A sweep should touch the threshold as designed, but not drag so hard that it marks the floor or keeps a self-closing door from closing.
Measure, install and test
DOE’s job aid sets out a simple sequence:
- Measure each side of the doorway, and the top, to size the weatherstripping. Record the gap at several points, because a worn threshold or shifted frame is rarely uniform.
- Measure the door bottom for a sweep or door-bottom seal.
- Notch the ends of the side pieces so they fit tightly against the top piece, unless the manufacturer already notched them.
- For screw-on strips, fasten them securely with the short screws the manufacturer supplies.
- Check that the door still opens, closes and latches smoothly, and adjust as needed.
The job aid’s stated goal is less air leakage while keeping, or improving, normal door operation. After installation, also check the deadbolt and any closer. Look at the sill from outside during rain, because weatherstripping must not send water into the sill or wall.
For a door between an attached garage and the house, or any fire-rated door, use parts compatible with the door’s required fire, smoke and self-closing performance. Do not drill or cut a labeled door without checking with its manufacturer or a qualified professional. Renters should get the landlord’s approval before replacing seals or thresholds.
Related guides
Sources
Checked October 3, 2026: