Weatherstripping

Why Is My Front Door So Drafty?

If you can feel a cold line around your front door in January, the door is no longer sealing. In Ottawa that is rarely the glass or the wood — it is almost always the seal, the sweep, or the way the door sits in its frame.

Find the leak before you fix it

On a windy day, run the back of your hand slowly around the closed door — top corners first, then the latch side, then along the bottom. Cold air at the bottom points to a worn door sweep. Cold along the sides or top points to compressed or cracked weatherstripping. A draft only near the latch usually means the door is not pulling in tight, which is an alignment problem, not a seal problem.

Worn weatherstripping

Weatherstripping is the flexible seal around the frame that the door presses against. Ottawa's swing from humid summers to deep cold hardens and flattens it within a few years. Once it stops springing back, the seal is gone. Replacing it is straightforward and one of the cheapest ways to cut a draft — our guide to replacing door weatherstripping walks through it, and our weatherstripping service handles it if you would rather not.

A failing door sweep

The sweep is the strip along the bottom of the slab that seals the gap to the threshold. It wears faster than anything else because it drags. If daylight shows under your door, the sweep is done. Watch for the signs you need a new door sweep — and if water comes in too, see how to stop water coming under a door.

A door that no longer sits square

Houses settle. Hinges loosen. When the slab shifts even a few millimetres, it stops meeting the seal evenly and a draft opens at one corner. New weatherstripping will not fix a door that is out of alignment — the slab has to be brought back square first. That is front door repair, and on older frames it can overlap with frame repair if the jamb has moved. The fix is often as simple as adding a longer screw to the top hinge to draw the slab back toward the hinge side, or shimming a hinge to push it the other way — but knowing which way to move it takes a trained eye.

How Ottawa's freeze-thaw makes drafts worse

Our winters do not just sit at a steady cold. Daytime sun and overnight lows push the temperature back and forth across freezing dozens of times a season, and that freeze-thaw cycle is hard on a door. Moisture works into tiny gaps, freezes, expands, and slowly opens them wider. The same cycle frosts the inside of the frame and can leave a thin skin of ice at the threshold, which holds the sweep off the sill so it no longer seals. By February a draft that started as a hairline gap in November can be wide enough to feel from across the room. This is also why drafts that vanish in spring come straight back the next cold snap — the underlying gap never closed, the milder weather just let the seal relax back into contact. For more on the mechanism, see why cold air comes through a door.

What a drafty door actually costs you

A leaking front door is not only uncomfortable — it runs your furnace harder all winter. A finger-wide gap around an exterior door adds up to the same opening as a small window left cracked open from December to March, and your heating bill carries that load every month. The draft also pulls cold air across the floor of your entryway, makes the hall feel chilly no matter how high the thermostat goes, and in a bad case lets enough humid indoor air reach the cold frame to leave frost or condensation that drips and stains. Set against that, a seal or sweep replacement is one of the highest-return repairs on the house. We break the math down in our guide to the cost of heat loss from a damaged door.

DIY versus calling a pro

If the draft traces to a worn seal or a tired sweep, that is a reasonable weekend job — buy the matching profile, pull the old strip, and fit the new one for even compression. Where homeowners get stuck is the alignment case: you reseal the whole door, it looks perfect, and the draft is still there because the slab is not landing on the seal squarely. Adjusting hinges, planing a binding edge, or correcting a frame that has racked out of square is fiddly and easy to overshoot, and an over-tightened door is as much trouble as a loose one. A door that has dropped on its hinges and now catches the frame is a sagging door repair, not a weatherstripping job. If you have done the seal and sweep and cold air still gets through, that is the signal to call.

When it is worth a call

If you have replaced the sweep and seal and still feel cold air, the door or frame is out of true and needs adjusting. We diagnose the draft, fix the cause, and seal it for the winter — flat-rate, same day in most of Ottawa and the Valley.