How To Seal Bottom Of Uneven Garage Doors

Your garage is supposed to be a safe haven for your car, motorbike, garden tools and other equipment. Unfortunately, it's all too common for garage doors to be installed on an uneven surface creating gaps. Gaps underneath a garage door are problematic as they can allow for rain, leaves, cold air and rodents in.
Since even small gaps under your door can lead to water ingress, it's essential to create a strong seal between the bottom of the garage door and the floor.
Ways to fix gaps caused by uneven garage floors include repairing the concrete under the door, installing a floor-mounted threshold seal or adjust the closing position of the door.

1. Repair the Concrete Under The Door

In some cases, uneven gaps under the garage door are caused by poorly laid or deteriorating concrete. If the underlying concrete is otherwise sound, it may be possible to apply a layer of screed under the door to create a level surface. If the uneven floor is the result of loose concrete which has developed cracks, a more extensive repair of the concrete base may be required.

A well-laid concrete ‘slab’ will usually have relief cuts at pre-determined intervals to avoid cracking in unwanted areas because of shrinkage and thermal expansion. It is a good idea to consult with an experienced builder to determine the requirements of a new concrete floor in your garage.

2. Install a Floor-Mounted Threshold Seal

Installing a garage door threshold seal is a convenient and cost-effective way to block a gap between the bottom of your garage door and the floor. A threshold seal provides a robust physical barrier behind the door, like a dam, to block the likes of water, debris and pests.

When the floor under the garage door is uneven, it is important to use a threshold seal that is specifically designed for a variable gap. A ramp-profile threshold seal is best suited to uneven gaps as it can be positioned to sit further forward under the garage door where the gap is larger to maintain a good seal along the inside edge of the door.

3. Adjust the Closing Position Of Your Door

Unlike typical up-and-over style garage doors that open as a single piece, sectional and roller garage doors are comprised of multiple articulated panels. Electrically operated sectional and roller garage doors allow the user to adjust the closing position of the door to create good contact between the factory bottom seal and the concrete floor.

By properly adjusting the closing position of your garage door as directed by the manufacturer, you may be able to reduce or eliminate small gaps caused by an uneven floor.


In conclusion, there are several effective ways to deal with an uneven gap under your garage door to protect the belongings in your garage. From installing a ramp-profile threshold seal to carrying out remedial work on your concrete floor, sealing the gap under your garage door is a great way to improve the environment inside your garage.

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