Drafty Doors:
Weatherstripping, Door Sweeps and Thresholds

Front and back doors

An exterior door seals in two places. Weatherstripping runs up both sides and across the top of the jamb, and the door presses against it when it closes. At the bottom, a sweep on the door meets the threshold. When either one wears out, the door still latches fine and the gap is easy to miss.

Russ’s most common wording is short: weatherstripping at the referenced door was inadequate, with a recommendation to correct it to help prevent air leaks and pest intrusion. The details vary. In Tigard, daylight and air leaks were clearly visible around the front door’s gasket. In Gresham and Vancouver, the weatherstripping had come loose from its slot in the jamb. A Portland front door had no permanent sweep, just a loose replacement sliding off the bottom.

Doors that are out of square cause their own gaps. In one Portland house, the front door hit the frame at the top and didn’t touch the weatherstripping at the bottom, so no amount of new seal would close the gap until the door was adjusted.

Aftermarket foam and tape

When a door is drafty, people stick things in the gap. Russ found aftermarket foam gaskets in the tracks of an original metal sliding door in Vancouver, foam strips between double front doors in the same house, and extra weatherstripping added over the factory seals on Portland French doors. Tigard front door hinges and weatherstripping had paint overspray on them.

These are clues more than problems. They usually mean the original seal failed or the door doesn’t close evenly, and someone was cold.

The door between the garage and the house

This is the door Russ writes up most, in Vancouver, Lake Oswego, Oregon City, Beaverton and Sherwood. It’s an entry door like the others, but what’s on the other side is a garage with car exhaust, gas cans and a water heater. A gap at the bottom of this door was written up in Beaverton because it breaks the separation between the garage and the living space.

In Oregon City and Sherwood, the fire-rated door between the garage and the house was missing weatherstripping, and in Oregon City the strike plate too. The post on the garage-to-house fire separation covers what that door and wall are supposed to do.

Overhead garage doors

The big door has its own seals: a rubber astragal along the bottom and a stop molding with a flexible flap along the sides and top. Russ found bottom seals loose or torn in Portland and Vancouver, side stops not lying flat against the door on new builds in Vancouver and Springfield, and seals missing entirely on Lake Oswego and Portland garage doors.

Gaps around a garage door let in rain, leaves and rodents more than they cost on a heating bill (most garages aren’t heated). In Battle Ground, staining on the concrete inside the pedestrian garage door showed where water had been coming in at the bottom.

Thresholds, jambs and crawlspace hatches

Under the sweep is the threshold, and under that, the subfloor. A threshold that isn’t sealed or flashed lets water run under the door. Russ found active rot at a Portland basement walk-out threshold, decay at the bottom of door jambs in Lake Oswego and Battle Ground, and a Lake Oswego balcony door with moisture staining that showed water was getting past the threshold. A bent metal threshold in Estacada had no support underneath.

Inside, the interior crawlspace hatch is the door nobody thinks about. Russ found hatches with no weatherstripping in Portland, Vancouver and Tigard, and one in Hillsboro with weatherstripping coming loose. A hatch in a hallway closet that doesn’t seal is an open path for crawlspace air, damp and cold, straight into the house.

What Russ checks

He opens and closes a representative sample of exterior doors, checks that they latch, and looks at the weatherstripping, sweep, threshold and the bottom of the jamb. He checks the garage entry door and the overhead door seals, and the crawlspace and attic hatches. He doesn’t measure air leakage. A blower door test, often part of an energy audit, does that, and the Portland Home Energy Score post covers where that comes up.

For windows and the rest of the openings, the agent guide to windows and doors covers fogged glass and failed seals. To set up an inspection, you can book online.