How to Seal the Bottom of a Garage Door?

The quickest way to seal the bottom of a garage door is by replacing the existing bottom seal (weather stripping) that runs along the length of the door.

Step 1: Measure & Purchase

Getting the right seal is the most important first step. An incorrect seal won’t fit or provide a proper barrier.

• 1. Measure: Use a tape measure to find the exact width of your garage door.
• 2. Identify Type: Pull out a small section of your existing seal to see its shape. The most common have a “T” shape on the ends that slide into a track. Buy a replacement with the same shape and width.
• 3. Purchase: Buy a seal that is at least a foot longer than your door’s width to have extra for trimming.

Tools Needed:

Tape Measure

Step 2: Remove the Old Seal

• 1. Safety First: Close the garage door and unplug the electric opener.
• 2. Access the Seal: Raise the door to a comfortable working height.
• 3. Remove Retainer Screws: Some doors have screws holding the retainer; remove them.
• 4. Slide it Out: Use pliers to grip one end of the old seal and slide it completely out of the track. If it’s stuck, a flathead screwdriver can help pry the track open slightly.

Tools Needed:

Pliers, Flathead Screwdriver, Safety Glasses

Step 3: Clean the Retainer Track

This is a critical step. A dirty track will make it very difficult to slide the new seal in.

• 1. Initial Cleaning: Use a brush or compressed air to remove loose debris, cobwebs, and dirt from the retainer tracks.
• 2. Degrease: Spray a cleaner or degreaser into the tracks.
• 3. Wipe Down: Use a rag to wipe the tracks thoroughly until they are clean and dry.

Tools Needed:

Cleaner/Degreaser, Rags, Stiff Brush

Step 4: Install the New Seal

This step is much easier with two people—one to feed the seal and one to pull it.

• 1. Lubricate: Spray the clean tracks with a silicone-based lubricant. This is essential.
• 2. Feed the Seal: Fold the new seal in half lengthwise to make a “U” shape. Insert the “T” ends into the tracks at one end of the door.
• 3. Pull it Through: Continue to feed the seal while the second person gently pulls it from the other side. Ensure it doesn’t bunch or twist.

Tools Needed:

Silicone Lubricant, A Helper (recommended)

Step 5: Trim & Secure

Properly finishing the job prevents the new seal from sliding out of place over time.

• 1. Center the Seal: Make sure the seal is centered on the door, with an equal amount of excess hanging off each end.
• 2. Trim: Use a sharp utility knife to trim the excess, leaving about an inch of extra seal on each side.
• 3. Fold and Tuck: Fold the extra inch back into the end of the retainer. This helps lock it in place.
• 4. Crimp (Optional): Use pliers to gently crimp the ends of the aluminum retainer tracks to pinch the seal and prevent it from sliding.

Tools Needed:

Utility Knife, Pliers

Step 6: Test Your Work

A final check ensures you have a perfect seal and a protected garage.

• 1. Reconnect Power: Plug the garage door opener back in.
• 2. Close the Door: Fully close the garage door.
• 3. The Light Test: With the garage lights off, look for any daylight coming in under the door. Small, uneven gaps might indicate an uneven floor, which may require a larger seal.
• 4. Adjust if Needed: If the door opener struggles to close, the seal may be too thick. If there are large gaps, you may have the wrong type of seal.

Tools Needed:

Your Eyes!

Effort vs. Impact of Each Step

This chart shows which steps have the biggest impact on a successful installation. Don’t skip the important ones!

Final Project Checklist

✔Garage door width measured accurately.

✔Correct type and size of replacement seal purchased.

✔Garage door opener unplugged for safety.

✔Old, worn-out seal completely removed.

✔Retainer tracks are completely clean and free of debris.

✔Tracks lubricated with silicone spray.

✔New seal installed without twisting or bunching.

✔Excess seal trimmed and ends secured.

✔Door closes fully and no light is visible underneath.