How to Replace a Garage Door Bottom Seal
Open the garage door, remove the retainer channel from the bottom panel, slide the old seal out, clean the retainer, slide the new seal in from one end, reattach the retainer, and close the door to check for gaps. The job takes about 30 minutes and requires no special tools.
- Time
- 30 min
- Frequency
- every 3-5 years (or when cracked/brittle)
- Difficulty
- easy
- Cost
- $20
What you'll need
- Flathead screwdriver or pry bar
- Tape measure
- Utility knife or scissors
- Dish soap and water (as lubricant)
The steps
- 1
Open the garage door
Raise the door to a comfortable working height. If you have an automatic opener, disconnect it by pulling the manual release cord so the door stays in place. You need the bottom panel at about chest height so you can work on it without kneeling on the ground.
- 2
Remove the retainer from the bottom panel
The bottom seal sits in a U-shaped or track-style retainer bolted or screwed to the bottom edge of the lowest door panel. Remove the screws or pry the retainer tabs loose with a flathead screwdriver. Some retainers are one piece across the full width. Others are two pieces that meet in the middle. Set the hardware aside.
- 3
Slide the old seal out
Once the retainer is detached, slide the old rubber seal out from one end. If it is stuck, spray a little dish soap and water mixture into the channel as lubricant. Pull steadily from one end. The seal may come out in pieces if it is badly deteriorated. Remove all remnants.
- 4
Clean the retainer channel
Wipe the inside of the retainer with a damp cloth to remove dirt, old rubber fragments, and corrosion. A clean channel lets the new seal slide in smoothly and sit evenly. If the retainer is bent or badly corroded, replace it. New retainers cost a few dollars at any hardware store.
- 5
Slide the new seal in from one end
Feed the new seal into the retainer channel starting at one end. The T-shaped or bulb-shaped cross section of the seal locks into the retainer's track. Apply dish soap to the channel as lubricant if the seal is tight. Work it in a few inches at a time. Do not force it or stretch it. The seal should be snug but should slide with moderate effort.
- 6
Reattach the retainer to the door
Hold the retainer with the new seal up against the bottom panel and screw or bolt it back into the original holes. Start with the center fasteners to keep it aligned, then work outward to each end. Trim any excess seal flush with the edges of the door using a utility knife.
- 7
Close the door and check for gaps
Lower the door slowly and watch how the seal meets the garage floor. It should compress evenly across the full width with no daylight visible. If one side is higher than the other, the door may need track adjustment. If the seal bunches in the middle, it was installed with too much slack. Pull it taut and retrim.
Why the bottom seal matters
The bottom seal is your garage's first defense against the outside. It runs the full width of the door and compresses against the floor every time the door closes. When it works, it keeps out rain, snow, cold drafts, dust, leaves, and pests. When it fails, everything gets in.
Water is the biggest concern. A heavy rainstorm drives water against the door, and even a small gap lets it sheet across the garage floor. Standing water damages stored items, promotes mold on drywall, and can rust tools and equipment. If your garage is attached to the house, water can wick into the living space through the shared wall.
Pests are the second concern. Mice can squeeze through a gap as small as a quarter inch. Snakes, spiders, and insects exploit the same gaps. A tight bottom seal is a physical barrier that works 24 hours a day without chemicals or traps.
Cold air enters at the bottom because cold air sinks. In winter, a missing or cracked seal creates a constant draft that chills the garage and any rooms above it. If you have living space over the garage, a failed seal directly affects your heating bill.
Types of garage door bottom seals
Three seal profiles cover most residential doors. The difference is in the cross-section shape.
T-style seals have a flat base with a T-shaped stem that locks into the retainer channel. The flat bottom sits flush against the floor and creates a wide contact patch. This is the best option for smooth, level garage floors. It wipes clean against the floor like a squeegee.
Bulb seals have a round, hollow tube at the bottom. The tube compresses and conforms to the floor surface. This makes bulb seals the better choice for uneven, cracked, or sloped floors where a flat T-style seal would leave gaps.
Beaded seals have a round bead on each side that snaps into a grooved retainer. They are common on newer doors with proprietary retainer systems. Check your existing seal's profile before buying a replacement. A T-style seal will not fit a beaded retainer and vice versa.
How to measure
Measure the width of your garage door from one edge to the other. Add one foot to give yourself trimming room. A single-car door is usually 8 to 10 feet wide. A double-car door is 16 feet wide. Most replacement seals are sold in 9-foot, 16-foot, or 20-foot lengths.
Also measure the retainer channel. The T-stem or bead of the seal must match the retainer's slot width. Most residential retainers accept a 3/16-inch or 1/4-inch stem. If you are not sure, bring a piece of the old seal to the hardware store and match it.
If your retainer is damaged, you can buy a new one. Aluminum retainers last the longest. Plastic retainers are cheaper but crack in cold weather after a few years. Replace a cracked retainer at the same time as the seal.
Signs it needs replacement
Visible damage. Cracks, tears, chunks missing, or rubber that has hardened and turned gray. Flexible rubber should bend easily between your fingers. If it snaps or crumbles, it has dried out and lost its ability to seal.
Daylight under the door. Close the garage door and look for light at the bottom from inside the garage. Any visible light means the seal is not making full contact with the floor.
Water after rain. If you find water inside the garage near the door after a rainstorm, the seal has failed. Check the seal first before assuming the door needs adjustment.
Pests getting in. Finding insects, mice, or leaves inside a closed garage usually means the bottom seal has a gap. Walk the length of the door and look for spots where the seal is compressed flat, torn, or missing.
Frequently asked questions
- What is the difference between T-style and bulb garage door seals?
- T-style seals have a flat T-shaped cross section that presses flat against the floor. They seal best on smooth, level floors. Bulb seals have a round tube shape that conforms to uneven surfaces. If your garage floor is cracked or slopes, a bulb seal is a better choice.
- How do I measure for a replacement garage door seal?
- Measure the width of your garage door and add one foot. Standard single-car doors are 8 to 9 feet wide. Standard double-car doors are 16 feet wide. The extra foot gives you trimming room. Also check the retainer channel width. Most residential retainers accept seals with a 3/16-inch or 1/4-inch T-stem.
- Why does water get under my garage door?
- The bottom seal is cracked, compressed flat, or missing sections. Water follows the path of least resistance, and even a small gap lets water sheet in during heavy rain. A new seal that compresses firmly against the floor stops water penetration. If the floor itself slopes toward the door, you may also need a threshold seal on the floor.
- Can I use the garage door while the seal is missing?
- Yes, but you should not leave it that way for long. A missing seal lets water, insects, rodents, leaves, and cold air into the garage. Mice can fit through a gap as small as a quarter inch. Replace the seal as soon as possible after removing the old one.
Products you'll need
This section contains affiliate links. We may earn a commission at no cost to you.
Universal Garage Door Bottom Seal (16ft)
Rubber weather seal to keep out water and pests
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