Our garage door, pictured below, is right on a sidewalk that slopes downward slightly as it moves past the garage. The result is that one side of the garage door is 4 inches below grade while the other side is 1 inch above grade. There is no drain. A previous owner attempted to keep water out by pouring the cement bump right at the door you see in the picture below to force water to run past the garage door. The problem is that the bump is cracked and does not form a seal with the garage do, so a little water (not to mention draft) still gets into the garage when it rains.

I'm considering repouring the bump, ensuring it is more flush with the garage door, and adding weather stripping. What do you guys recommend? Alternatives? Is it worth considering some type of drain?

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  • 1
    Wow! Gotta love that construction from days gone by. I have a garage built right at ground level too. Maybe consider a trench drain in front of the door too.
    – ArchonOSX
    Nov 21, 2015 at 20:57

2 Answers 2


@ArchonOSX's answer is good, as long as the local drainage is good enough. If not, I'd install a trench drain that extends further down the slope to where it can discharge back onto the sidewalk, but that depends on the situation.

I'm guessing the door is 8' wide, and the sidewalk falls 5" across it, which means the sidewalk has about 1/2" per foot pitch.

Let's say you install a level trench in front of the door, starting 1" below the door and with a depth of 4" (with a grate on top). At the downhill end of the door the trench bottom will be 4" below the sidewalk.

Then you have to get rid of the water. Drains should have 1/8" per foot pitch, so the sidewalk will fall 3/8" per foot faster than the drain. So, it will take another 11 feet before the sidewalk is below the bottom of the drain. If you have that kind of space you can just extend the trench to that point and then turn it back to the sidewalk.

If not, improvise.

  • Improvise? How?
    – Yehuda_NYC
    Nov 22, 2015 at 1:30
  • 1
    @Yehuda_NYC Um, specifying how to improvise makes it no longer improvisation. I've offered a specific answer that makes assumptions as to the environment. It's quite possible that my answer won't work, but a related one will. Hence the reference to improvisation. Nov 22, 2015 at 3:17

Ok try this.

Excavate in front of the garage down deep enough to bury two (or more?) plastic drums with ½" to 1" holes drilled in them. Wrap them with landscape fabric and refill the area with crushed stone.

You could also add a trench drain up against the sidewalk that drains into the drums.

If you get a torrential rain you will still have issues but for smaller rain bursts it should hold enough water to keep it out of your garage.

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