How to Replace Garage Door Weatherstripping: Bottom Seal, Side Seals, and Top Seal (2026)

Frequently Asked Questions

How do I know if my garage door weatherstripping needs replacing?

Visible signs include: rubber or vinyl that is cracked, torn, flattened, or pulling away from the door or frame. Functional signs include: daylight visible around the door perimeter when the door is closed, rain blowing in under or around the door, drafts felt near the door in winter, or evidence of rodents and insects entering the garage. The bottom seal takes the most abuse — if you can see light under the closed door when standing inside with the lights off, the bottom seal needs replacement. Side and top seals are less prone to wear but should be inspected every 3 to 5 years.

What is the difference between a garage door bottom seal and a threshold seal?

The bottom seal (also called a door bottom or astragal) attaches to the bottom edge of the garage door itself and hangs down to contact the floor. It moves up and down with the door. A threshold seal (also called a garage door threshold) is a rubber or vinyl strip that adheres to the garage floor directly under where the door closes. The two work together: the bottom seal on the door meets the threshold on the floor to create a complete barrier. You can use either or both. A threshold seal alone does well where the floor is uneven because it fills gaps that a flexible door bottom can't bridge. Using both provides maximum protection.

What size bottom seal do I need for my garage door?

Measure the width of your garage door (standard residential widths are 8, 9, 16, and 18 feet). Bottom seal is sold by the foot or in pre-cut lengths — buy slightly more than your door width and cut to fit. More importantly, measure the T-slot or retainer channel at the bottom of your door if it has one. Most modern steel doors use a T-slot retainer (a metal channel with a T-shaped groove). The replacement seal must have a matching T-profile to slide into this channel. Older wood doors may be nail-on style. Bring your old seal to the hardware store if possible, or photograph the retainer channel.

How do I replace the side weatherstripping on a garage door?

Garage door side seals are typically attached to the door stop molding (the wood or metal trim that the door closes against on each side). The seal is usually a flexible vinyl or rubber flange that is nailed or stapled to the stop. To replace: remove the old seal by pulling the nails or staples (a pry bar and pliers work well). Cut the new seal to length and nail it to the stop molding, with the flexible flange pointing inward so it flexes against the door face when the door closes. Position the flange to make full contact with the door surface without buckling. Use 1-1/4 inch galvanized roofing nails, spaced 6 to 8 inches apart.

Can I replace garage door weatherstripping myself or do I need a professional?

All four types of garage door weatherstripping — bottom seal, side seals, top seal, and threshold — are straightforward DIY projects requiring only basic tools. No special garage door knowledge is needed. The most physically demanding part is working on a step stool to reach the top seal and side seal near the top corners. The bottom seal replacement on a T-slot door requires sliding the new seal in from the side — no lifting the door is required. Total time for all four seals: 2 to 4 hours for a first-timer, 1 to 2 hours for a second attempt.

What material is best for garage door weatherstripping — rubber or vinyl?

For cold climates, EPDM rubber or thermoplastic rubber (TPR) outperforms PVC vinyl because rubber stays flexible at low temperatures (down to -40°F for EPDM), while vinyl stiffens and cracks in cold weather. For moderate climates, vinyl is durable and cost-effective. For the bottom seal specifically, look for a bulb-style or T-style seal with a 3/16 to 1/4 inch bulb diameter — this provides enough flexibility to conform to minor floor irregularities. Garage-door-specific weatherstripping products (not generic door weatherstrip) are designed for the abuse of daily cycles and UV exposure.

Replacing garage door weatherstripping: (1) Bottom seal (most common failure): measure the door width, buy the matching seal type (T-slot, nail-on, or retainer bar style), cut to length, and slide or nail in place. A worn bottom seal lets in rain, pests, and cold air.

Garage door weatherstripping is one of the most cost-effective home maintenance tasks you can do. A complete set of replacement seals costs $30 to $80, takes an afternoon to install, and pays back in reduced heating and cooling costs, a drier garage floor after rain, and the end of the annual rodent infestation. Most homeowners ignore weatherstripping until it has completely failed — but if you can see light around your closed garage door, water comes in during rain, or the garage temperature swings dramatically with outside temps, all four seals need attention now.

This guide covers every seal location: the bottom of the door, both sides, the top, and the floor threshold. You do not need to call a garage door technician for any of this.

What You Need

• Garage door bottom seal with T-retainer — the primary water and pest barrier; matches your door width; $15–$30
• Garage door side weatherstrip seal — flexible vinyl or rubber flange for the side stop molding; sold by the foot or in 9-foot kits; $10–$25
• Garage door top seal / header seal — the horizontal seal across the top of the door opening; $8–$20
• Garage door threshold seal kit — adhesive floor strip that meets the bottom door seal; $20–$40
• Galvanized roofing nails or staple gun — for attaching side and top seals to stop molding; $5–$12
• Silicone or construction adhesive — for adhering the threshold seal to the concrete floor; $6–$15

Estimated total cost: $50–$100 to replace all four seals on a standard single-car door. Double-door: $80–$150.

Step 1: Inspect All Four Seal Locations

Before ordering materials, do a systematic inspection. Close the garage door, go inside, and turn off the lights. Wait for your eyes to adjust. Any daylight visible around the door perimeter — bottom edge, sides, or top — indicates a failed or missing seal at that location.

Then look at the seals themselves with a flashlight:

Bottom seal: Pull the door down and examine the rubber strip along the bottom edge. Cracked, torn, flat (no longer has a bulb profile), or pulling out of its retainer channel? Replace it.

Side seals: Look at the vertical strip of rubber or vinyl where the door meets the side stop molding on each side. Is it continuous? Does it make contact with the door? Torn sections, gaps, or seals that have pulled away from the stop mean side seals need replacement.

Top seal: The horizontal strip at the top of the door opening, behind the door when it’s closed. Look for cracks, tears, and missing sections. This seal is often forgotten but becomes obvious when rain blows in above the door.

Floor gap: With the door closed, use a flashlight to check for gaps between the door bottom and the floor, especially at the ends of the door where floors are often uneven. If the center seals but the ends gap, a threshold seal will solve this.

Note which seals need replacement and measure each location before ordering.

Step 2: Replace the Bottom Door Seal

The bottom seal is the most important and the one most likely to be in bad shape.

Identify your retainer type. Most modern steel garage doors have a T-slot retainer: a metal channel along the bottom edge of the door with a T-shaped slot that the seal slides into. Older wood doors may have a flat nail-on retainer or no retainer at all.

For T-slot retainer doors: Slide the door up about halfway so the bottom is accessible. Look at the ends of the bottom seal — there are usually plastic end caps or the seal simply runs to the edge of the door. Remove the end caps or plastic retainer stop at one end. Slide the old seal out of the retainer channel from one side. Measure and cut the new seal to length (door width plus about 1/2 inch — you can trim flush after installation). Slide the new seal into the retainer channel from the same end, positioning the T-profile into the T-slot. Push the new end cap back in place. Lower the door and check contact with the floor along the entire width.

For nail-on retainers: Remove all the nails or staples holding the old seal. Pull the seal off. If the retainer itself is bent or damaged, straighten it with pliers or replace it. Cut new seal to length. Nail through the flange at the top of the seal into the retainer every 6 to 8 inches.

For doors with no retainer: You can add a T-slot retainer to any door — they’re sold as retrofit kits and screw to the bottom edge of the door. This is worth doing if the door has never had a proper seal. Alternatively, a surface-mount door bottom that screws directly to the door face works for any door type.

Cost for bottom seal replacement only: $15–$30 in materials. Time: 30 to 45 minutes.

Step 3: Replace the Side Weatherstrip Seals

Each side of the garage door has a stop molding — a board or metal channel that the door closes against. A flexible rubber or vinyl flange attached to this stop creates the side seal.

Remove the old seal. Most side seals are nailed or stapled to the stop molding. Use a pry bar or pliers to pull out the fasteners and remove the old seal strip. Note which way the seal is oriented — the flexible flange should angle inward to press against the door face, not outward.

Cut the new seal. Measure the full height of each side stop from the floor to the top corner, where the side stop meets the horizontal stop. Add 1 inch. Cut the new seal to that length with a utility knife.

Install the new seal. Position the seal on the stop molding with the flange pointing inward. The flange should contact the door face when the door closes. Nail through the body of the seal (not the flange) into the stop molding using galvanized roofing nails, spaced every 6 to 8 inches. The flange must be free to flex — do not nail through the flange.

Check contact: close the door slowly and watch whether the flange contacts the door face along its full length. If there’s a gap in the middle due to the stop bowing slightly outward, add a nail in that area to pull the stop closer to the door.

Repeat for the other side.

Step 4: Replace the Top (Header) Seal

The top seal runs horizontally across the top of the garage door opening, pressing against the top of the door when it’s closed. It is often the last seal homeowners notice has failed, because the damage it causes — water blowing in over the top of the door during driving rain — is intermittent.

The top seal is typically attached to the horizontal stop molding at the top of the opening. It uses the same installation method as the side seals: pry off the old seal, cut new seal to length, and nail through the body (not the flange) to the stop.

The flange should point downward and press against the top edge of the door when it closes. If the original stop molding is set too far back from the door, you may need to reposition it closer so the flange makes contact. This is done by removing the stop, moving it forward 1/4 inch, and re-nailing it.

Step 5: Install a Threshold Seal on the Floor

Even with a good bottom seal on the door, uneven garage floors create gaps. A threshold seal permanently attached to the floor compensates for floor irregularities that the door bottom can’t bridge.

Clean the floor where the threshold will go. Sweep and vacuum, then degrease with a citrus cleaner or acetone. The adhesive will not bond to a dusty or oily concrete floor. Let the floor dry completely.

Do a dry run. Close the door, mark the floor at the center bottom point of the door. This is approximately where the threshold should sit — positioned so the door’s bottom seal presses against the threshold’s ramp, compressing the seal without being so tight that it makes the door hard to open.

Apply adhesive. Most threshold kits include construction adhesive in a tube. Apply a serpentine bead along the bottom of the threshold. Some kits recommend two-sided tape as a temporary hold while the adhesive cures — use this if included.

Set the threshold. Press the threshold onto the floor at the marked position. Lower the door onto the threshold to check the compression fit. The door should close fully and the threshold should not prevent it from latching. Adjust position before the adhesive sets.

Cure time: 12 to 24 hours. Do not drive over or move the threshold until the adhesive has fully cured.

Step 6: Test and Adjust All Seals

With all seals installed, do a complete test:

1. Close the door fully and go inside the garage. Turn off the lights and look for daylight. No light should be visible at any point around the perimeter.

2. Run water from a garden hose along the outside of each seal location. Check inside for any water intrusion.

3. Open and close the door several times. The bottom seal should compress against the floor (or threshold) without causing the opener to strain or the door to bind. If you have an automatic opener, run it through 5 to 10 cycles and verify it completes each cycle normally — an overly tight seal can trigger the opener’s torque limit and reverse the door.

If the door reverses due to the new seal, adjust the opener’s down-force setting slightly — most openers have a down-force adjustment screw. Increase by one click and test again. See your opener manual for the specific adjustment procedure.

Long-Term Maintenance

Inspect weatherstripping annually — ideally in early fall before cold weather sets in. The bottom seal takes the most abuse (vehicle traffic, UV, and floor contact) and is the one that needs replacement most often, typically every 5 to 7 years in moderate climates and every 2 to 3 years in climates with extreme temperature swings.

Vinyl side and top seals in protected locations can last 10 to 15 years if they’re not physically damaged. EPDM rubber seals last even longer. Lubricate rubber seals annually with a silicone spray (not petroleum-based lubricant, which degrades rubber) to prevent drying and cracking.

A complete set of new seals costs $50 to $100 and takes an afternoon. It is far cheaper than the water damage, mold remediation, or pest control that a leaking, uninsulated garage eventually requires.

Related Reading

• How to Lubricate a Garage Door — keep the door running smoothly alongside new seals
• How to Insulate a Garage — the next step after sealing gaps for a conditioned garage
• How to Fix a Garage Door That Won’t Close — when the seal isn’t the problem and the door itself isn’t functioning
• How to Fix a Broken Door Sweep — repair a worn door sweep on an entry door using similar techniques
• How to Fix a Broken Garage Door Bottom Seal — focused guide on replacing just the bottom seal when the sides and top are still intact