Getting your home ready for winter is never an easy task—especially if you have to seal the gap beneath your garage door. Aside from letting heat waft out of your home, a gap between your garage door's bottom panel and your concrete floor can allow rain, snow, leaves, and other materials to dirty your garage. Perform one (or both) of the following tasks to seal your gap:
Replace Your Bottom Panel's Weatherstrip
The weatherstrip connected to your bottom panel only lasts so many years. After being scraped against your garage floor and being exposed to constant sunlight, your weatherstrip can become torn or cracked. If it's not replaced, it will eventually begin falling off your bottom panel.
To replace your weatherstrip, disconnect your automatic opener (either by shutting off the power supply or disconnecting the trolley) and manually open your garage door until you can comfortably access your weatherstrip. Clamp a pair of locking vice grips under a roller on each side of your guide track to secure your door in its position.
There are a few common ways that weatherstrips are connected to garage door panels. The most common connection design uses two channels that hold the edges of a weatherstrip and force the strip into a flexible U-shape. The channels will either be U-shaped or T-shaped.
If your garage door assembly uses one of these designs, pull the seal out by hand or use a flat screwdriver to pry the edges of your weatherstrip out of their channels. Purchase a replacement weatherstrip with the appropriate channel shape and slide it into the channels to install it.
If your seal is connected to your bottom panel by nails and adhesive, then you'll have a more difficult time replacing it. To replace this type of seal, you'll need to pry out the nails using the claw side of a hammer and slide a putty knife between the seal and panel to break the adhesive connection.
To prepare your panel for your replacement seal, apply an adhesive remover to the bottom of your panel and chip off any leftover adhesive.
Purchase universal weatherstripping from your local home improvement store and cut a strip to match the length of your garage door. Use a caulking gun to apply adhesive to the bottom of your panel and press your weatherstripping against the adhesive. Hammer your nails back into the existing holes in the bottom of your panel as you press each section of weatherstripping against your bottom panel.
Install A Threshold Seal
If your bottom panel's seal is still intact, but still lets air flow into and out of your garage, then install a threshold seal. Threshold seals attach to your garage floor instead than your panel. Similarly to weatherstripping, threshold seals are available at your local home improvement store.
To install a threshold seal, thoroughly clean the area where your garage door touches the ground. If there are any oil stains in this area, remove them with TSP (trisodium phosphate). Next, measure the distance between the sides of your garage door opening and, if necessary, cut your threshold seal accordingly.
Place your seal where you want to install it and close your garage door on top of it to make sure that it won't disrupt the cycle of your door. Outline the position of your threshold seal with a brightly-colored crayon. Remove your seal and place two thick beads of adhesive just inside of your interior and exterior outline. Fill the area between these two beads of adhesive with a zig-zagging line of adhesive.
Carefully guide your threshold seal back into the position in which you outlined it and press it against the floor to ensure that it makes contact with your beads of adhesive. Read the packaging of your adhesive to determine its cure time. Don't close your garage door or otherwise disturb your threshold seal until after your adhesive completely cures. If you do, your threshold seal will not adhere correctly.
If you have trouble installing a threshold seal or replacing your bottom weatherstrip, then contact a professional garage door repair technician to finish the job for you. By leaving these tasks to a professional, you can ensure that your garage door will no longer allow heat to freely escape your home.