How to Replace Garage Door Bottom Seal Weatherstrip

Over time garage door bottom seal weather strip can dry rot , flatten and compress down to the floor. Old weatherstripping tends to allow water and other debris into your garage. Old seals also decrease energy efficiency by letting cold air flow freely under the door. Garage door astragal replacement is an easy project for most home owners and can be completed in less than 15 minutes. Here are some steps to follow in order to properly replace the bottom weather strip on your overhead door.

Step One: With the door in the closed position, disengage the opener from the door by pulling down the red Liftmaster 41A2828 emergency release cord . Then raise the door to an eye level position, clamping the door off with a pair of vice grips if necessary.

Step Two: Using a razor blade, cut a 2-3 inch sample piece of seal off your door so you can properly identify what type of seal you will need. Match the type of seal you have to the products offered in our garage door parts store. The most common types of bottom seal are T-Type Seal, J-Type Seal and Beaded Seal. 

• T Type Bottom Seal
• T Type Wayne Dalton Skinny T Bottom Seal
• J Type Bottom Seal
• Beaded Bottom Seal
• P-Bulb Overhead Door Bottom Seal
• Wood Door Bottom Seal

Step Three: Measure the width of your garage door so you know how many feet to order. Common garage door widths are 16ft for a double door and 9ft for a single car door. You may also want to measure the width profile of your seal. Selecting a wider profile bottom seal may help seal low spots. The most common profiles are 3.5″ and 4.5″ , up to 6″ widths are available. If you have multiple doors you will need to pay attention to the color of the seal. Common colors are black and gray, although yellow is available for commercial applications.

Step Four: Remove you old bottom weather seal by pulling on one end along the bottom retainer. Sometimes the bottom retainer can get bent and make removing the old seal difficult.  Using a flat head screwdriver, you can pry up on the bent retainer channel to allow the seal to move freely. If necessary, use a razor blade to cut the old weather seal in half along the width of the door. This will help make it easier for you to remove the old seal.

Step Five:  Clean all dirt and debris from the aluminum retainer on the bottom of your garage door.  Spraying a light application of soap based window cleaning solution to your bottom retainer can help loosen up debris and make it easier to install your new seal. Windex is a better option for cleaning and lubricating the track than WD-40. Using a flat head screwdriver, make sure your bottom retainer isn’t pinched together. Loose or bend any areas of the retainer where the bottom seal will have difficulty sliding through.

Step Six: Fold your new garage door bottom seal into a “U” shape and begin slide the T end of the seal into the bottom retainer channels. Slowly, drag one end of the seal through the bottom channel. You will have to alternate back and forth between pulling the new seal along and feeding it into the channel. Two people on this task would be the most efficient, especially on double wide doors.

Step Seven: After pulling the bottom weather seal across the full width of the door, pull five more inches of seal out the end of the track extra. You will be folding the extra seal hanging out the end back into the channel. Push any excess astragal back into the channel space. This will keep the seal in place and help protect against shrinkage.  Repeat this step on the other side of your garage door.

Step Eight: Remove your vice grips from the vertical track and lower the door to the ground. Re-engage your garage door opener trolley to reconnect the garage door opener. If you see any daylight coming through the ground you will need to adjust your seal accordingly. Always test your garage door opener and adjust the limit and force controls on the motor casing as needed. If the door hits the floor and goes back up your will need to adjust the travel.

Bonus: Does your garage door bottom seal get flat and smash to the ground quickly? Consider installing and old garden hose or back rod in the space between your aluminum bottom retainer and seal. This will help prevent your astragal seal from flattening too quickly and will provide a tighter seal.