How to Install a Garage Door Seal

Maintaining a good garage door seal is essential for keeping the temperature in your garage, and therefore the temperature in your home, at a good level in both the winter and the summer. A surprising amount of heat can be lost through the small crack at the bottom of your garage door, and that’s not even accounting for drafts that you can get inside from air blowing under the door. Having an insulated garage door is a good first step--in fact, we always recommend having an insulated garage door--but an insulated door is worthless if you’ve got air leaking through beneath it.

So how do you stop this heat transfer from taking place under the garage door? By installing and maintaining a garage door seal. In this article we’re going to walk you step-by-step through how to install a garage door seal.

Measuring the Garage Door

Before you can know the right weather stripping to buy for your garage door, you need to measure its width, its height, and its thickness. Then you need to gather the tools for the job.

For installing a garage door seal you may need:

• A garage door weather stripping
• A new retainer and self-tapping screws
• A tube of exterior caulk
• A can of wood sealer (if your garage door is wood)
• A rubber threshold
• Dish detergent to act as a lubricant
• A socket wrench
• A screwdriver
• Strong scissors
• Adhesive
• An extra pair of hands

Remove the Old Garage Door Seal

The retainer is the piece of metal or plastic that holds the garage door weather seal in place. You may not need to replace it, but if your weather seal is wearing out then it’s probably a good idea to replace the retainer, too.

Raise the door enough that you can easily access the weather stripping alongside the bottom. In an ideal situation, you could be able to slide the weather stripping out of the retainer, but odds are good that a worn-out weather strip will not slide easily, might tear, and will be difficult to work with either way. However, if the retainer is in good condition, and all goes perfectly, you merely need to slide the old weather stripping out and slide in the new. 

But here’s what to do if that doesn’t work. 

If the weather stripping is in a retainer, as opposed to being nailed to the bottom of a wooden door, then you can begin to remove the retainer. This is done with your screwdriver and socket wrench. You may need to pry and fight the retainer to get it off. (This is a normal thing. The retainer is what comes into contact with the ground every time that you close your garage door, and it’s not hard for it to get a little stubborn to remove.) If it’s particularly troublesome, you may need to pry it off and remove it in pieces. 

If you’re able to get the weatherstripping out of the retainer without having to remove the retainer, you should wash the retainer with dish soap, a cloth, and water. 

On a wooden door, things are easier. Odds are good that the rubber seal has been nailed to the bottom of the door, and you can simply pry it off with a claw hammer. Once the stripping has been removed, then patch up any cracks or holes with wood sealant and let it cure.

Now, whether metal or wood, you should have the weather stripping off your door. 

What To Do If Your Retainer Didn’t Need to Be Removed

If you were able to simply remove your weather stripping from the retainer without damaging the retainer, and if the retainer has no rust to indicate it needs to be replaced, then first use a soapy wet rag--heavy on the dish soap--to lubricate the retainer, and then begin to slide the weather stripping into place. Once it gets all the way down the track, all you need to do is trim off the excess stripping to fit. If there are caps for the ends of the retainer (usually plastic) simply pop them back on and give them a light tap with a rubber mallet to make sure they’re secure.

What To Do if Your Retainer Needs to Be Replaced. 

If the retainer needs to be replaced, make sure that you clean the surface of the bottom of the door completely, and then--with the help of another set of hands--raise the new retainer up into place and begin to screw or bolt it in. Then use exterior caulk to seal the edge of the retainer.

Once it is secure, you can follow the instructions listed above for lubricating and sliding the new weatherstripping into the retainer. 

What To Do If You Have a Wooden Door

With a wooden garage door, replacing the garage door seal is as simple as nailing a new seal into place with, again, the help of another set of hands. (Replacing any garage door seal by yourself is a very difficult job.) Nail it securely down into well-sealed wood, and you should be good to go.

Taking Things One Step Further: Installing a Threshold

It’s not standard for most builders to install thresholds in garage doors, but they can literally save you hundreds in heating and cooling bills due to the temperature loss. 

Start by cleaning your cement with water and degreaser, then rinse thoroughly and let it dry. Once dry, roll the threshold out into place with the hump on the inside of the door. Then bring the door down and make sure that the threshold is in exactly the right place. Cut off the excess so it fits perfectly. Then use a chalk line mark where the threshold will be, and begin to lay down the adhesive. Once done, carefully affix the threshold in place. Close the door and leave it shut until the adhesive completely dries.