How to Seal a Garage Door Threshold

closed garage door
  • 2-4 hours
  • Beginner
  • 65-120
What You'll Need
Garage door threshold kit
Utility knife
Pencil or wax crayon
Soap and water
What You'll Need
Garage door threshold kit
Utility knife
Pencil or wax crayon
Soap and water

A garage door threshold seal will add further protection from the weather. It will also help keep your garage more comfortable if you are using it as a workshop. The seal will prevent air from flowing in under the door, which keeps the area more temperate. Here’s how you can do this yourself.

Clean the Area

It is important to make sure that any dirt and debris is cleared away from the area where you will be installing the seal. Open the garage door and make sure the lip of the door is clean of dirt and debris as well. Because the garage will need to be open through most of this process, it is probably wise to wait for a good weather day as well. If it is windy or rainy, all you will get done is cleaning the area as the weather affects the process. Make sure there are two inches of clearance on each side from where the door closes. This needs to be your area of cleanliness.

Follow the Instructions

open garage door to empty garage

Most likely your kit will include easy-to-follow instructions for sizing the threshold within the kit. It needs to be the exact size for your open garage door. Most of these rubber thresholds can easily be trimmed to fit the space needed with a utility knife. As always, measure twice and cut once.

Test the Threshold

Once the area is clean and dry, put down the threshold to test the seal. Be sure to adjust the threshold as necessary in order to form a tight seal. The bump of the threshold should form against the inside of the garage door when closed.

Trace the Threshold

Use a pencil to trace both the inside and outside of the threshold on the garage floor.

Remove the Threshold

Once you have the threshold traced properly, you can remove it and place it to the side. You will need to apply the adhesive next.

Apply Adhesive

The garage door threshold kit should come with its own adhesive that will be easy to apply. Be sure to spread it in a zigzag pattern in order to maximize surface adhesion. This will also form a tight seal between the threshold and the floor itself. Apply the adhesive between the two straight lines you traced earlier.

Set Threshold in Place

Carefully lay the threshold down over the adhesive, keeping it aligned with the outline made earlier with the pencil. As you lay the threshold down, be sure to apply pressure in order to form a tight seal between the threshold and the floor. This also maximizes the adhesion so the seal will not later come up.

Close the Garage Door

front of a closed garage door

When you close the garage door, make sure that it does not shift off of the outline laid down. To ensure this, close it manually instead of with the automatic motor.

Allow the Adhesive Time to Dry

Generally, this takes about 18 to 24 hours to dry. Do not drive over the threshold at that time.

Adding the seal to your threshold will add several benefits. If you use your garage as a work or living space this will be a great advantage for you. Installing a seal won’t take a long time and is basic enough for anyone to accomplish.