A closed exterior door should seal out cold air completely — but a draft doesn't always mean the door is broken or needs replacing. Most of the time, the problem comes down to a few specific points where the seal has failed. Finding exactly where cold air is getting in makes the difference between a quick fix and wasted effort.
How to Find Where the Draft Is Coming From
Before you replace anything, locate the source. Hold a lit candle or incense stick close to the door perimeter on a cold, windy day — any flickering will reveal air movement. You can also slide a piece of paper between the door and the frame and close the door on it. If the paper pulls out easily, the seal is weak at that spot. Work your way around all four sides, including the bottom.
The most common entry points are:
The door sweep (along the bottom edge)
The weatherstripping on the top and sides
The gap between the door and frame caused by misalignment or warping
Cracks in the door frame or threshold itself
The Most Likely Causes
Worn or compressed weatherstripping is the leading culprit. Foam and rubber weatherstripping compresses over time and eventually stops making full contact with the door. If you can see daylight around the edges of a closed door, or if the weatherstripping looks flat, cracked, or peeling, it needs to be replaced. This is one of the most DIY-friendly fixes there is — adhesive-backed foam or V-strip weatherstripping is available at any hardware store, and installation takes less than an hour in most cases.
A damaged or missing door sweep is nearly as common. The sweep runs along the bottom of the door and blocks the gap between the door and threshold. These wear down from constant friction, and in climates with significant rainfall — which the Pacific Northwest has plenty of — the moisture exposure accelerates deterioration. Replacement sweeps come in several styles (automatic, door-bottom, threshold seal) and are generally straightforward to install with basic tools.
A misaligned or warped door is trickier. Doors shift over time as the house settles and as wood absorbs and releases moisture. If your door sticks in summer and drafts in winter, or if the gap between the door and frame is uneven — wider on one side than the other — the door itself may have moved. Sometimes adjusting the hinge screws (replacing standard screws with longer ones to pull the hinge tighter to the frame) can correct a mild sag. More significant warping or settlement, however, may require rehanging the door or shimming the frame.
Gaps in the frame or threshold can also be the source. Exterior caulk degrades, and small cracks around the door frame allow cold air to infiltrate before it even gets to the weatherstripping. Check the exterior side of the frame where it meets the siding and apply exterior-rated paintable acrylic latex caulk if you find gaps.
What Homeowners Often Get Wrong
One common mistake is replacing weatherstripping without checking door alignment first. New weatherstripping won't seal properly if the door isn't sitting squarely in the frame — you'll just compress it unevenly and be back to the same problem.
Another is overlooking the threshold. If the adjustable threshold seal has sunk or the threshold itself is damaged, no sweep will compensate fully. Thresholds can often be adjusted with a screwdriver; replacements are available at hardware stores if adjustment isn't enough.
Finally, adding more weatherstripping on top of old, deteriorated material rarely works. Remove the old material completely before applying new product.
When It Makes Sense to Call Someone
DIY-friendly repairs — weatherstripping, door sweeps, and exterior caulking — cover the majority of exterior door drafts. Where it gets more complex is when the door frame has shifted significantly, the door itself is warped beyond minor correction, or the threshold requires replacement along with other carpentry work. At that point, getting the door properly sealed often involves more than a hardware store trip.
If you've worked through the obvious fixes and still feel cold air coming through a closed exterior door, EVN Handyman can assess and repair the problem throughout the Portland metro area.