4 Garage Door Bottom Seal Types: Pros, Cons, and More

In many homes, the garage space is for more than just parking a car. To keep your garage comfortable, adding the right garage door bottom seal types will reduce drafts and prevent water, rodents, and insects from creeping through the gaps under the garage door.

Once you protect the space with garage door weatherstripping, you should seal your garage floor or hire a local garage floor coating contractor to put down a coating that works well with your garage floor drain diagram. Before spending money on a coating, though, you’ll want to weatherproof the door. We compiled a list of the four best garage door bottom seal types so you can match your door’s design to its ideal seal.

1. P-Shaped and T-Shaped Bulb Seals

The T-shaped bulb seal has a cylinder at the bottom with a T-shaped connector extending from the top. The connector slides into a T-shaped groove on the bottom of the door.

The P-shaped bulb is almost identical, but it has a P-shaped connector at the top that slides into the P-shaped groove underneath the door.

Also called tube seals, the bulb-shaped garage door bottom seal types are extremely popular. Many hardware stores carry the bulb seal, so they’re easy to find. They tend to be reasonably priced, too.

As the door goes down, the cylinder flattens against the pavement, creating the seal. This makes it a great choice to keep water from coming in under a garage door. However, it does work better on flat concrete, as it may not completely close large gaps on heaving concrete.

This seal prevents air movement under the door, saving energy and helping with temperature maintenance inside the garage.

To use these bulb seals, you need a T- or P-shaped track attached to the bottom of the door. These bulbs most often fit on a single track, although you may be able to find products made for double tracks that accommodate two T- or P-shaped connectors.

The flexible bulb consists of rubber or rubberized vinyl. However, it’s not a thick material, so rodents could gnaw through it if there’s a gap due to uneven cement.

Best for: Flat concrete garage floors

2. Beaded Seal

A beaded seal forms a U-shape when installed, but it arrives as a flat strip of rubber or rubberized vinyl roughly 3 inches in width. Each end of the piece has a connector, meaning it requires a double track on the underside of the garage door.

A pair of T-shaped connectors is by far the most common, although you may also see a pair of round or P-shaped connectors.

Although it forms a U-shape when installed and when the garage door is up, the piece flattens against the concrete when the door closes. It’s a highly flexible material that will compress tight to the ground if you have flat concrete in the garage.

The piece of material has several raised ribs or beads spread across its face. When the strip is flat to the ground under the garage door, the ribs hold some parts of the material a tiny fraction of an inch above the ground. This prevents the material from freezing solidly to the ground in areas that collect moisture.

Even with the slight gap that the ribs or beads create, the beaded seal does not allow any significant air movement underneath it, providing the energy efficiency that you want to see from garage door weatherstripping.

This design is not a good choice for uneven concrete, as it won’t fit tightly enough across the space. Mice could gnaw through the thin material if you have significantly uneven concrete.

Best for: Doors that may freeze to the ground

3. J-Shaped Seal

Many homeowners find that a J-shaped seal effectively seals the underside of their garage door. Here’s how it works: when you close the door, you’ll see a J-shape along the ground as the flap in the material curls into this shape underneath the pressure of the door closing. The flaps do extend outside the width of the door just a bit.

This design creates an extremely tight seal that protects against moisture, airflow, and critters, whether you’re using rubber or rubberized vinyl materials.

The J-shape is not one of the most common garage door bottom seal types, but it appears regularly on storage units and containers because they need strong weather protection.

It can be a challenging design to install, though, as it requires a single-channel retainer to secure it to the bottom of the garage door. You have to add the retainer along the bottom of the door, and the retainer must match the width of the door. To simplify installation, the J-shaped seal often ships with a matching retainer, which increases the price.

Best for: Areas that need maximum durability

4. Threshold Seal

The threshold seal is a horizontal piece of rubber that extends the full length of the garage door, which could be several feet. Along its width of a few inches, it’s thicker in the middle and tapered at either end.

Rather than attaching it to the door, you’ll glue or bolt it to the concrete floor, meaning you must drive over it each time your car enters the garage. When the garage door comes down, it rests on top of the rubber.

This design is great for uneven concrete floors, as the thickness of the rubber can make up for gaps. The garage door's weight can compress some areas of the rubber while lightly touching other parts of it. This creates a tight seal between the garage door and the threshold on the uneven floor surface.

If installed incorrectly, though, the threshold seal could come loose as you drive over the top of it. Once it’s out of alignment, it could make it difficult for the door to close completely. The uneven application of force could damage already weakened or older parts of a garage door system. If so, you may be looking at a garage door repair cost, which averages about $250.

If you are unsure whether the threshold garage door bottom seal type is the best fit for your garage door, or if you want help with installation, local garage door installers should be able to provide the advice you need.

Best for: Uneven garage floors