Weatherstripping

Signs You Need a New Door Sweep

The door sweep is the strip along the bottom of your door that seals the gap to the threshold. It wears faster than any other seal because it drags every time the door moves, and a worn one is an open gap at floor level.

What a door sweep does

A sweep closes the gap between the bottom of the slab and the threshold. That gap is where cold air pours in and warm air leaks out, so a good sweep matters most in an Ottawa winter. Because it physically contacts the threshold every cycle, it is the first seal to wear out — long before the side weatherstripping.

The signs it is done

• Daylight under the door: the clearest sign. If you can see light along the bottom from inside, air is moving through that gap.
• A cold draft at floor level: stand near the door on a windy day. Cold air pooling at your feet points to the sweep, not the side seals — the test in our drafty door guide.
• A torn, flattened, or hardened sweep: look at it. A rubber or vinyl blade that is split, curled, or crushed flat no longer seals.
• It drags or has come loose: a sweep set too low scrapes and wears fast; one hanging loose has lost its fasteners.
• Water or grit getting in: a failed sweep lets water under the door too — see stopping water under a door.

Why a worn sweep matters

Beyond the draft and the heating cost, a failed sweep lets water reach the sill and the bottom of the jamb, and that is a leading cause of frame rot. A two-minute gap at the bottom of the door can, over a few winters, turn into a frame repair. It is the cheapest seal to replace and one of the most worthwhile.

Types of door sweep

Not every sweep is the same, and matching the type to your door matters. A screw-on sweep mounts to the face of the slab and is the easiest to replace. A slip-on or channel sweep slides onto the bottom edge. An automatic or drop sweep lifts as the door opens and drops to seal as it closes, which is useful where a fixed blade would drag on a threshold or flooring. For an Ottawa exterior door, a sweep with a flexible rubber or silicone fin holds up best to the cold, while a stiff brush sweep is better suited to interior or garage-entry doors. If you are buying a replacement, take the old one with you or measure the door width and the gap you need to close.

How Ottawa winters wear a sweep faster

The sweep at the bottom of the door takes the brunt of our climate. Through the winter it drags through grit, road salt, and slush tracked onto the threshold, all of which chew up a rubber blade. Freeze-thaw is harder still: meltwater and ice build up at the sill, the blade freezes stiff and cracks, and a sweep that sealed fine in November can be split and leaking by February. Salt left on the threshold also dries out and hardens the rubber over time. This is why exterior sweeps in Ottawa wear out faster than the manufacturer's rating, and why it is worth checking the sweep every fall before the cold arrives rather than waiting for a draft to tell you.

Replacing it right

The sweep has to match the door's clearance — high enough to clear the threshold and let the door swing, low enough to seal. Too low and it drags and wears; too high and it leaks. If you are confident with a screwdriver, swapping a screw-on or slip-on sweep is a short DIY job; the step-by-step is much the same as in our guide to replacing weatherstripping. Pairing a quality sweep with good side weatherstripping is the combination that holds a winter; our notes on the best weatherstripping for Ottawa winters cover the side seals. We fit sweeps and full seals through our weatherstripping service.

When the sweep is not the whole problem

Sometimes a new sweep does not fully close the gap, and that points past the sweep itself. If the door has dropped on its hinges, the slab swings low on one side and no sweep will sit evenly — that is a sagging door repair. If the threshold has loosened or the sill has gone soft from years of water, the sweep has nothing solid to seal against, which is threshold and sill repair. And a sweep that keeps shredding fast usually means the door is dragging, not that the part is bad. When the door, frame, and threshold are sound, a good sweep finishes the job.

Quick to fix

A new sweep is a fast, inexpensive job that pays for itself over a heating season. If you see light under your door, it is time. We replace sweeps and seal the whole door, flat-rate across Ottawa and the Valley, and while we are there we check the threshold, the side seals, and the door's alignment so the fix actually holds through the winter rather than leaking again at the first hard freeze.