Garage Door Weather Seals: Bottom Seals, Jamb Stops and Thresholds

The four seals every door needs

A properly sealed opening has a seal on all four edges, and each one has a different job.

• Bottom astragal — the U-shaped or bulb rubber seal in the bottom retainer; the hardest-working seal
• Jamb weatherstrip (stop molding) — vinyl trim with a flexible flap pressing on the door face
• Header seal — the same flap across the top section
• Section joint seals — the tongue-and-groove or shiplap design between panels

When the floor is the problem

A sloped, cracked or worn slab leaves a visible light gap that no bottom seal can close. Two fixes work.

• A taller bulb-style astragal that conforms to modest floor irregularities
• A garage floor threshold bonded to the slab, which also blocks driveway runoff
• Both together on badly sloped driveways that push water toward the door

Signs your seals have failed

Daylight visible along the bottom or sides with the door closed, water tracking into the garage after a storm, leaves and pollen accumulating inside, a cracked or flattened bottom rubber, curling vinyl jamb trim, or insects and rodents appearing in the garage. Any of these is a same-visit fix.

What sealing does not fix

Sealing controls air, water and pests, not heat conduction through the panels. If the garage still runs brutally hot with good seals, the door itself is uninsulated and the next step is a three-layer door. We check both on every maintenance visit and tell you which one is actually costing you comfort.

Frequently Asked Questions

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