If you read our previous blog post about R-Value, you probably know that insulating your garage is an important step in keeping your utility bills down and making your garage a pleasant room to be in during the heat of summer or the cold of winter. But if you’re not interested in upgrading to a better insulated garage door, your next best bet might be adding weatherstripping (also called astragal) around your door. We’ll walk you through this simple DIY procedure for sealing the top, sides, and bottom of your door, all of which can be done on a tiny budget.

Some signs that your door is in need of weatherstripping are obvious. If a visual inspection of the door from outside shows that the door panels are warping, leaving a gap between the sides of the door and the frame of your home, that is an easy problem to spot. Also, if you can feel an air current running into your garage when you put your hand next to one these gaps, you can also be certain that your door needs some sealing. Even if you don’t notice these problems or if your door already has old weatherproofing, you might want to upgrade anyways if you have problems with the garage or nearby rooms staying out of alignment with the rest of the home. If  you have a finished room over the garage, for example, and struggle to keep this room at a normal temperature, you might want to step up your insulation game. Note also that if the walls of your garage are completely uninsulated, that might be a better place to focus your attention, if you have the time and money for a slightly more involved job.

As we leave summer’s hottest days behind, it isn’t unreasonable to go ahead and plan for the winter chill now! It is never a bad time to perform maintenance on your home, since these sorts of upgrades are simple ways to improve your quality of life and your home’s eventual resale value. Now is the perfect time to put some weatherproofing on your door, so that your home’s temperature will be fully controlled come winter.

Replacing the seal on the bottom of your door requires a different procedure than the seals on the top and sides. If you are replacing your bottom gasket, begin my measuring your door. Also, inspect the way that your bottom gasket is currently installed, if you have one. Some gaskets include a metal service track into which the rubber seal is mounted, and others have their rubber attached directly to the door. If your door does not already have a metal track, you will want to buy a kit that includes one when you upgrade, but if you already have a track you will only need to replace the rubber section.

To inspect your door or to work on the bottom gasket, we recommend that you first disable your door’s power by unplugging the opener or turning it off at the circuit box. Then, disconnect your door from the opener and manually lift the door. Raise it until the bottom edge is slightly below the bend in the track, then lock the door into place with clamps attached to the track on both sides of the door. Position the clamps so that the rollers cannot travel down the track and always treat your door with extreme care.

Now that you can access the bottom gasket, use a levering tool (a screwdriver will do in a pinch, but a pry bar of some sort would be best) to open the metal track and remove the old gasket. If the gasket cannot be pulled out of the metal track, take a utility knife and slice it lengthwise so that it separates into two long sections, each of which can be removed from the track. After removing the old gasket, clean the bottom of the door thoroughly.

If your original weatherstripping did not have a metal track, use a claw hammer to remove the securing nails or a screwdriver to remove securing screws. You will have to install the new metal track in place of the only rubber flap, but this procedure will make your garage door much closer to weatherproof.

Now that you have removed the old gasket, cut off a short section and take it to the home improvement store to find the appropriate size for a replacement. Buy a piece that is at least six inches longer than your door so that you will have extra on both sides. Once your door is correctly outfitted with a track, sliding in the new rubber strip should be very simple. Trim the excess from the ends and fold a short length back over inside the metal track so that the edges are flush with the sides of the door.

After removing your clamps, lower the door and reconnect the power. Hopefully the door will operate as normal still, but it is possible that this change has altered either the weight or the sitting height of the door such that your opener’s safety devices are triggering incorrectly. You should be able to search for how to program your opener as per manufacturer instructions, or call a garage door opener repair company and have a technician reprogram your opener for a small fee.

The process for installing or replacing weatherstripping on the sides or top of your door is somewhat simpler since these sections won’t have to sit between the floor and the door. Home improvement stores sell top and side seal kits or pieces in a range of colors and styles. The different options are designed to suit different situations, so ask an employee or expert if you’re having trouble deciding between two similar options. In general, it is a safe bet to go with Vinyl, PVC seal strips or rubber kits. Some are sold in long panels with faux-siding connected to the rubber, and some are sold as a rolled-up coil of rubber. If your door has an unusual shape (something besides a rectangle) you might find the coils easier to install.

If there is old weatherstripping on your door, removing it is the first step. Use a flat pry bar to get underneath the old weatherstripping and lever it away from the wall, removing nails and screws whenever possible. Then, if you are using solid panels, measure the openings you will have to fill and cut your new weatherstripping to matching size. Do not use the old strip as a measure because it may have been deformed by time or the removal process.

Next, make sure that your garage door is closed and place the weatherstripping such that the rubber edge is pressed completely against the door. It is easiest to begin with the top section if you’re installing separate pieces, although of course if you’re using one coil you will begin at one end. The rubber is easy enough to cut if you need to make small alterations, but in general you should be able to lay the rubber right up against the door’s panels without these cuts. The idea is to make as close as possible to a perfect seal, all of the way around your garage door. While holding the stripping in place, connect it to the frame underneath with galvanized finish nails or other hardware appropriate for outdoor use. Using a nail or staple gun will speed up this job, but cutting corners will result in reduced quality. This step is easier with a helper to hold the stripping in place, but is manageable for a homeowner working alone.

Some stripping comes with pre-marked positions for nails, but if yours does not then make sure to install enough hardware to resist the elements and to hold the seal flush against the door. Once you’ve installed the top piece, open and close the garage door to ensure that everything is still working properly. The seal should match up against the door when it is closed but not the panels at all during operation. Once you’ve checked the top sheet, close the door and install the sides in an identical manner.

Where two pieces of weatherstripping meet, such as the top corners, trim away the excess rubber at a 45˚ angle so that the two pieces do not form a gap between them. After each section is installed, check again to make sure that the door operates as normal.

After you have successfully installed or replaced all of the weatherstripping that you are planning to, congratulations! This simple and cheap upgrade can take less than an hour and save you money all season long, so consider investing in it today. Check the insulation after operating your door as normal for a few days to make sure that nothing has shifted or moved, and check against after a week of regular use. There are also measures you can take to hide the nail heads from the weatherstripping, such as covering them in caulk or wood putty. These finishing steps are simple to execute and are already covered in hundreds of online tutorials.


We hope that you’ve enjoyed this tutorial and that it has helped you insulate your garage and home! This sort of simple procedure is a great way to build your confidence as a DIY homeowner and work up to larger projects, but it is still a great improvement to make on your home.

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