How do you stop drafts around a garage door?

A drafty garage door is not just uncomfortable in a Denver winter. Cold air infiltration through an attached garage raises heating costs and can freeze pipes that run through the shared wall. The fix usually costs $50 to $150 in parts and a few hours on a Saturday.

Start with the Bottom Seal

The bottom seal is a rubber or vinyl strip attached to the door's bottom edge. It presses against the floor when the door closes and forms the primary barrier against drafts, water, and pests. Over time, the seal hardens, cracks, or wears flat and stops conforming to the floor surface.

To check yours: close the door and look along the bottom edge from inside. If you see light or feel cold air along any section, the seal needs replacement. A standard T-slot seal slides into a metal retainer channel on the door's bottom bar. Replacement seals cost $15 to $40 for a single-car door and $25 to $55 for a two-car door. Installation takes 20 to 30 minutes with no special tools.

If your floor is uneven or has a significant crown in the middle, a standard flat T-seal will not contact the floor evenly. A bulb-style seal has a rounded profile that compresses more and fills small irregularities better. It costs a few dollars more per foot but is the right choice for floors that are not perfectly level. Many older Colorado garages have concrete slabs that have settled unevenly over the years, and a bulb seal handles that variation much better than a flat T-seal.

Check the Side and Top Weatherstripping

Side weatherstripping runs vertically along both door-stop boards and presses against the door's face when closed. This sealing strip is often the second-largest gap source after the bottom seal.

Look for compressed, flattened, cracked, or missing sections. Vinyl and rubber side seals last 5 to 10 years before hardening in Colorado's dry climate and UV exposure. Replacement strips cost $10 to $25 per side and are sold by the foot at home centers. Pull the old strip out of its channel or pry off the stop board if the seal is stapled on, then press or staple the new strip in.

The fit matters: the strip should press lightly against the door face when closed. Too tight creates friction that makes the door bind. Too loose leaves a gap.

The top seal runs along the top of the door frame. It is often the most neglected piece of weatherstripping because the gap there is smaller. On a windy Colorado day, a failing top seal funnels cold air across the ceiling and into the insulated wall space. Replacement top seals cost $10 to $20 and tack in place with staples or finishing nails.

Seal Location	Signs of Failure	DIY Parts Cost
Bottom seal	Light or air gap at floor	$15 to $55
Side weatherstripping	Gap along edge	$10 to $25 per side
Top seal	Draft at top of door	$10 to $20

How Door Alignment Creates Drafts

A door that sits crooked in its opening leaves gaps on one or both sides even if the weatherstripping is new. Uneven gaps along the side seals after a fresh replacement point to an alignment issue rather than a seal problem.

Track misalignment is the most common cause. If one vertical track is pulled in or out relative to the other, the door hangs at a slight angle. You can see this by looking at how the door panels sit in the frame from outside. A visible taper where one side has a wider gap than the other confirms misalignment.

Before calling for track work, check whether the door's bottom bracket bolts have loosened and allowed the roller to shift. Retighten any loose hardware before assuming the tracks are bent. On older Colorado garages with original hardware, bracket bolts loosen over years from the vibration of daily use and temperature cycling. A quick check with a socket wrench costs nothing and may solve the problem.

Drafts Between Door Sections

Air can also leak through the horizontal hinges between door sections, especially on older doors with worn section-to-section seals. Run your hand along each horizontal seam on a cold, windy day. If you feel airflow at any point, the panels have shifted or the section seals have failed.

Some sectional doors have rubber strips pressed between panels. These wear out on older doors. Replacement is possible on most models and costs $20 to $40 in parts per section. If the sections themselves have bent apart at the corners, a panel replacement or track realignment is needed to restore the original fit. This is a less common problem but shows up on doors that have been hit by a vehicle or that have old, fatigued hardware throughout.

Combining Air Sealing with Insulation

Sealing drafts and adding insulation work best together. The Department of Energy's guidance on air sealing notes that insulation performs at its rated value only when airflow through gaps is also addressed. A well-insulated door with drafty edges will still feel cold inside on a bitter morning because the cold air enters faster than the foam slows heat transfer.

If you are adding foam panels to the door, replace the bottom seal and side weatherstripping at the same time. The combined job costs $75 to $200 in parts and makes the garage noticeably warmer without touching the heating system. On an attached garage that shares walls with the living space, this combined fix can make the adjacent rooms feel warmer too by reducing the cold wall effect.

On a detached garage, the improvement is mostly comfort rather than energy savings, unless you heat the space. Either way, stopping drafts also stops water intrusion and pest entry, which have their own repair costs if left unaddressed through a Colorado winter.

One final check that many homeowners miss: the gap between the door and the concrete jamb wall on each side. Many older garages have a gap between the rough framing and the finished drywall or masonry that is not covered by the side weatherstripping. This gap runs vertically behind the door stop board and can be sealed with expanding foam or caulk before reinstalling the door stop. It is invisible once the weatherstripping is in place but can be a significant air entry point if left open.

Also check the threshold between the garage and the house door at the interior entry point. This personnel door between the garage and the living space is just as important for draft control as the main garage door. A door sweep on the bottom of the interior door and fresh weatherstripping on the frame creates a second barrier that helps even if the main garage door has some remaining gaps.

Taken together, the bottom seal, side and top weatherstripping, section seals, threshold seal, and interior door weatherstripping form a complete draft control system. Each piece costs under $30 and takes 30 minutes to replace. Done all at once in October, they protect the garage through the full Front Range winter without any additional intervention.

G Brothers Garage Doors can assess door alignment, replace seals, and fix track issues causing gaps. We serve the Denver metro and Front Range with free estimates, same-day service on most sealing jobs, licensed and insured.