The best door seal will depend on whether the garage door still has the threshold channel. You can get a new channel, the rubber for the channel, or just put rubber on the floor.
Watch Out 1: If your garage floor has a deep dip under the door, a standard rubber seal will not fill that gap. The channel is stiff and straight, and it will actually pull the door bottom back up where it might have been sagging before. The best course is to re-surface the floor, but barring that, put down a floor seal as well as a channel replacement to fill in big gaps.
Watch Out 2: Use a soapy solution to pull the rubber through the channel. The rubber has good friction to prevent movement. It’s going to fight you when you pull it from one end to the other. Soak the rubber in soap or create a soapy spray to grease things up while you work.
The Best Garage Floor Seal
The easiest and solution is to add a rubber seal to the garage floor where the door bottom meets the floor. You can do this whether or not there’s a channel on the door bottom. The door squeezes into the rubber, which pops up a bit to keep out wind and water.
I like the Universal Garage Door Threshold Seal for this job. Like most floor seal kits, it does not come with glue, so if you want to use an adhesive, you can separately choose the brand and color you want. Floor seals that include adhesive force you to use whatever color they send you. I prefer clear or black either Liquid Nails or Gorilla Glue. Click to view this seal on Amazon.
The Best Garage Door Rubber Seal Replacement
I like the Universal rubber kit because it has a healthy amount of rubber to fill in larger gaps. Not that any rubber should fill in very significant gaps, but this one goes a bit farther than others with less material.
If you have the door channel but not the rubber, then you can get a rubber kit that slides into the existing channel. The door already has a channel, so you need only thread the rubber through the channel and cut off any excess. The hardest part is threading rubber without soapy water. Don’t do it. The rubber resists movement, that’s how it keeps out the rain. Use a spray bottle of soapy water to make this an easy job. Click to see the rubber replacement kit on Amazon.
The Best Garage Door Channel Seal Replacement
The best solution is if the channel is missing is a channel-seal combination. You screw the top plate into the bottom of the door. If you need to thread the rubber through the channel, spray it with soapy water first. It’s a one-piece solution to replacing the channel as well as the rubber.
I like the Universal Door Channel replacement kit for wood or steel doors. It includes pre-drilled screw holes. The aluminum track holds the o-ring rubber that is sturdy down to -40 deg. F.
If the channel is solid but the rubber is missing, then the best solution is to get a threshold seal replacement. The trick to installing this type of threshold seal is to soak it in soapy water before installation. Rubber has a lot of friction. The soap allows you to slide the rubber through the channel without constantly hanging up along the way. Click to see the channel and rubber replacement kit on Amazon.