Garage door side and top seal worn? Drafts, leaks — and the fix

The bottom of a garage door gets all the attention, but the sides and top seal the door just as much. The weatherstripping runs down the two vertical jambs and across the header — usually a flexible strip of vinyl or rubber fixed to the stop molding, the thin trim the door closes against. It's what keeps out the wind, the driving rain, and the cold draft you feel in the garage on a winter morning. As the weather turns, a worn side or top seal is the difference between a garage that holds a little heat and one that leaks it all day.

Signs the side or top seal is worn

• Daylight or a visible gap down one or both sides of the closed door.
• A wind whistle or rattle along the edges on a gusty day.
• Rain tracking in at the sides, or drips from the top corners after a storm.
• The strip is cracked, hardened, curled away from the door, or torn loose.
• A draft you feel along the door frame, not just across the floor.
• Leaves, dust, or snow collecting just inside the vertical edges.

How the side and top seal differs from the bottom

The bottom seal rides in a retainer on the door itself and compresses against the floor. The side and top seal is the opposite: it's fixed to the frame, and the door presses against it from the inside when it closes. That's why a side seal can look intact and still leak — if the door sits slightly off, or the stop molding is warped, split, or rotted, the strip never makes full contact. The weatherstripping and the trim it's attached to are usually dealt with together, because new strip on old, cracked molding won't hold a seal for long.

What you can check yourself

• Close the door and look for daylight from inside during the day — the gaps show up clearly.
• Press the strip against the door edge. If it's stiff and won't flex back, it's past its life.
• Check the stop molding behind it. Soft, split, or rotted trim won't hold new weatherstripping.
• Note whether the gap is even top to bottom or worse at one end. An uneven gap can mean the door or track is out of alignment, not just a tired seal.
• Clear old dirt and caulk from the trim so you can see the real contact line.

What the replacement usually involves and costs

Replacing side and top weatherstripping is straightforward, low-end garage door work, and it's often done in the same visit as a bottom seal or a tune-up. The technician removes the old strip, checks the stop molding, replaces the trim if it's split or rotted, and fits new weatherstripping cut to the door's height and width. What moves the price is whether the wood trim also needs replacing, whether it's one side or both sides plus the top, and whether the door needs realigning first.

If the gap turns out to be an alignment problem — the door sitting crooked or the track pulled loose — that's a different fix, and a new seal alone won't solve it. Spring and cable tension are never part of a seal job and are pro-only work in any case, so don't force a door that feels heavy or binds. The technician confirms the price in person after seeing the door and the frame.