How to Seal the Sides of a Garage Door (No More Gaps!)

Garage doors are notoriously prone to letting in cold air, dust, insects, and noise. But the good news is that you can make them completely airtight if you’re willing to put in the effort. You see, the trick is in paying attention to all sides of the door — not just the bottom edge. Today, I’m going to show you how to fortify your garage door by sealing the top and sides.

Even though we’ll focus on the most neglected areas of a garage door, you shouldn’t exclusively work on them. That’s the tricky thing about garage doors. There’s plenty of room for air to move through the cracks at the bottom or even between the horizontal panels of the door.

Luckily, sealing the garage door should be easy enough as long as you have a good game plan. As it happens, that’s something I can provide. But before I do, let’s talk about the best thing you can do to prevent a draft from coming in from the sides.

How to seal the sides and the top of a garage door.

A Guide to Sealing the Sides of a Garage Door

Let’s not waste any time determining if you even need to seal the sides of your garage door. Suffice it to say, if you can fit so much as a pencil into the gap between your garage door and the door frame, you’ve got a problem on your hands.

But as I’ve said — fixing it will be a breeze, as long as you know what you’re doing. Here are the steps you need to take:

1. Get Everything You’ll Need

As always, the first thing we should discuss is the list of supplies you’ll need to get your hands on before you start working on the garage door. In this case, it’s relatively short. You’ll need:

  • The weatherstripping seal of your choice — they generally come in rolls and are often made to resemble painted wood
  • A hammer, pneumatic stapler, or drill
  • Some nails (which are usually included in the purchase of weatherstripping kits) or screws

If you don’t want to use nails or screws, you’ll also need something to clean the jamb with. You’ll need to start with a clean slate if you’re planning on using glue or sealant.

Speaking of which, caulking is a fantastic finishing touch even if you nailed the seal into the jamb. But I may be getting ahead of myself — we can’t talk about finishing touches before we’ve even begun.

For now, you should just measure the sides of your garage. The sum of the door’s height (multiplied by two) and width is the length of the seal you’ll need to purchase. While you’re waiting for that to arrive, let’s see what you can do about the old seals.

2. Tear off the Old Weatherstripping

If your current vinyl seal has deteriorated over time, you’ll need to dispose of it before installing a new one. To do that, you may need a few more tools at your disposal. If you don’t have a crowbar, you can use a sturdy kitchen knife to cut away the old caulk and lift the seal. Simply slide it under the vinyl strip and continue until you feel the first nail, then twist to lift it.

After you take off the top and the side seals, take stock of the door frame. You may have damaged the parts of the jamb in the process, especially if the seals were glued on. But don’t worry, that’s easy enough to fix.

Before you move on to the next step, sand and finish the jamb. Alternatively, if the act of stripping the seals managed to damage plaster, use the appropriate tools to fix the scuffs. Lastly, use wood putty to fill up any of the old nail holes that will be exposed once you install the new seals.

3. Prepare the Seal for Placement

Once you have a clean surface to work on, you can start preparing the seals. First, take a moment to measure the sides of the garage door again with a retractable measuring tape. It never hurts to double-check. Cut the seal down to size with a utility knife or circular saw if you have one in your workshop.

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As I have mentioned, garage seals usually come in rolls. The one I have linked above is a 7-foot product, but I’ve also found 30-foot ones. Just remember that you’ll have to cut two or three pieces out of the product you get, depending on the state of your old seals. It should also be long enough to handle slight miscalculations on your part.

If you’re replacing the top and both sides, you’ll want to cut and install the top first. Keep that in mind as you execute the following steps on my list. As you’ll see in this video, that is the best order, since it’ll allow you to alter the side seals to make them fit perfectly against the top one.

Lastly, before you press the seals against the door jamb, you’ll want to put your nails through the thicker part of the strips. The nails should be an inch and a half long and about 16 inches apart.

When you put them flush against the door, tap some of the nails to temporarily affix the seal. Don’t drive them all the way into the jamb just yet, though — you’ll have to check their placement first.

4. Check the Seal Placement and Nail It In

At this point, the seals should be loosely nailed into the garage door frame on the outside. Now, you just have to check if they’re in the right spot.

To do that, put your hands on the garage door and give it a push. Shift your position and keep an eye out for any gaps that may appear between the seal and the door.

If you spot any, take the closest nail out of the jamb and shift the seal closer to the door. Then shake the door again, to confirm the new placement.

Doing this will ensure that your seals will remain impenetrable even during a windstorm. So after you find the right spot for the seals, drive your nails into the seals completely. And remember: you should attach the top first, and then the sides.

5. Apply Caulk to the Gaps

If you used nails or screws to attach the vinyl seals, you may still see tiny gaps between them and the jamb. Despite their seemingly inconsequential size, they could make all the effort you put into sealing the sides of the garage door pointless.

Fortunately, there is a way to increase your chance of success: all it takes is a bit of sealant.

If you don’t want to go all-in with a caulking gun, you could probably get away with using a basic silicone sealant that comes in a tube. Whichever kind of applicator you choose, run it along the edge between the door jamb and the seal. Wear disposable gloves, so you can run a finger along the bead of sealant to smooth it out. That will also help the sealant plug the cracks that might have allowed air to flow in and out of the garage.

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Of course, if you used adhesive to attach the seals to the jamb, you don’t need to do this step. But as you might have guessed, I’m not a huge fan of that method. It just makes it more difficult to take the vinyl off when the time comes, resulting in damage you’ll have to address before installing the new seals.

Ultimately, using sealant too liberally creates more work for you. So it’s best to keep it on the edge of the vinyl strips.

Say Goodbye to Your Damp, Dusty, and Noisy Garage!

With only a few adjustments, your garage can become as tranquil as any other room in your house. But remember, side seals are only one part of the equation. If you want to seal your door completely, this guide can help you fill in the blanks.

On top of that, you may also want to thicken the door from the inside with MLV curtains or use some of the other garage soundproofing techniques. The measures you implement will depend on the way you like using your garage.

For example, if you just want to use your power tools in peace, focus on preventing the spread of the noise. However, if you want to be able to enjoy movies or games, you might want to improve the acoustics inside the garage, not just prevent sounds from coming in or going out.


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