You are planning to resurface the concrete floor of your garage but the threshold isn’t exactly even. There is a gap at one or even both of the corners that lets in air and even small rodents. You are wondering what can be done to correct it.

To get started, we contacted Garaga, the largest garage door manufacturer in Canada. They explained what could cause a situation like this and how to correct it, if possible.

The exterior drain

The most often seen case is linked to the lifting of the exterior drain. This situation is often encountered when garages are located in the basement of a house. Combine a drain that poorly removes water from rain or melting snow with the normal freezing and thawing process, and heaving will occur and you’ll get a drain that pushes up the concrete threshold of the door.


  • Depending on the extent of the problem, meaning the degree of heaving, it is very possible that more or less major excavation work is needed to ensure the water will freely flow out.
  • If the heaving is less than ¾” (2 cm), the good news is that most U-shaped bottom weatherstripping for garage doors ensures sealing to a height of 1 inch (2.5 cm).  However, for it to properly work as a weather seal, the section of the door must be able to rest on the threshold, without being crushed, but you cannot slip your fingers under.
  • There is also a longer 4 ¾-inch (12.1-cm) U-shaped bottom weatherstripping (see photo), used for some commercial doors, that can give you more room to adjust to a very uneven threshold.

The threshold is broken

It could happen that with the coming and going of your car, or simply by the small amount of concrete that was used, some places on the threshold will be broken.


  • You can install PVC weatherstripping on the threshold (see photo). It can be purchased in any good building material center.
  • There is also a solid aluminum bar (see photo) that can be screwed into the concrete. In cases where you can do it, try to install this bar as level as possible by using pieces of rubber to even it out in order to get the best possible results. If necessary, use repair cement to make everything as level as possible.

A poorly installed door

It could happen that the door was poorly installed at the start, and when that was done, the bottom section wasn’t leveled. Thus, you can find that in one of the two corners of the door, the U-shaped weatherstripping doesn’t touch the threshold. It may also be the case that the garage structure has moved or settled causing this type of situation.


  • If it is due to a poor installation, contact the company who installed your garage door (you should find its name on a sticker located on the door or door opener) to remedy the situation.

The garage door opener needs adjusting

The last case we can encounter is where it’s not just one corner of the door that isn’t touching the threshold, but the whole lower section doesn’t adequately touch the threshold and you can easily pass your hand under it.


  • The door opener isn’t fully pushing the door onto the threshold. The lowering of the door must be readjusted. The vast majority of electric garage door openers are equipped with a button to make this adjustment. Look on the motor housing and you should see an arrow pointing down and another pointing up.
  • With a flathead screwdriver, and your garage door remote, turn the screw used for adjustment left, around a ¼ turn. Operate the door with the remote, and see the result.
  • It is important to remember not to crush the U-shaped weatherstripping on the threshold. With a correctly adjusted door you should be able to slip your fingertips slightly under but not be able to pass under the threshold.

Ready to resurface your concreate floor?

We just covered the ways of correcting your uneven concrete threshold. If you are ready to resurface your concrete floor with epoxy paint, we can offer you two solutions: you can do it yourself and we supply the products you need, or we can do it all for you.

Contact us at 1 855 652-3866 (1 855 65 BETON). It will be our pleasure to show you the full range of colors that we carry. We can also supply you with a quotation completely free of charge. You can also view the different projects we have done, that could soon include yours!

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