I need a quick solution to fill a 2" gap between concrete curb that will handle the weather. It can be temporary as long as it works to block water intrusion.

Background: I'm the last house on the decline of a hill before going down into a valley. The city's storm drain is directly in front of my house. There's a 2" gap between the storm drain concrete and the curb.

My house has a basement and the last rain created a tunnel from this 2" gap to my basement. I doubt the city will be out in time for my request since there's another rain in a few days.

I've been considering foam type application, but unsure if it'll handle the pressure when the drain tends to back up a little and uncertain which foam to use for an outdoor application.

Editing for my solution: I ended up filling the inner cavity with backer rod crammed in there. Then went over it with hydraulic cement about 4" deep. Due to upcoming weather and cure time of the cement (7 days could be longer with 4" deep) I'll also put sandbags. Hopefully this will hold until city returns. Might arguably be overkill.

Could potentially use weather proof expansion foam instead of backer rod then cement or just fully use cement, but this was a temporary quick and dirty solution.

  • 1
    @Ruskes that stuff deteriorates in the sun. I'd fill the gap with sand or gravel (or even pipe insulating foam in the manner of backer rod) then use a polymeric filler (i.e. caulk) on top to seal.
    – Huesmann
    Jan 25, 2023 at 15:49
  • @Huesmann no it does not deteriorates in the sun, it is used on the outside to seal the gaps around the windows.
    – Traveler
    Jan 25, 2023 at 21:56
  • @Huesmann would you say a caulk like "Dap 18021 Concrete and Mortar Watertight Filler and Sealant" would do the job?
    – JGood
    Jan 25, 2023 at 23:59
  • @Ruskes I looked up some of the window ones and it does say to try and keep them out of the sun with paint, etc. I'll try to see if there's one that matches outside weather.
    – JGood
    Jan 25, 2023 at 23:59
  • @Ruskes I've used it, and seen it deteriorate.
    – Huesmann
    Jan 26, 2023 at 12:40

1 Answer 1


Since this is temporary, until the city enacts a permanent repair, try sand bags. Maybe some small enough to fit in the 2 inch gap and larger ones over those. Easily removed as well.

  • 1
    Sand bags are the de facto solution to flooding situations.
    – FreeMan
    Jan 25, 2023 at 13:56
  • Thank you! Looking into it for the gap. Was worried about the angling of the sand bag blocking water from the drain if placed around the crack plus street parking potentially causing an issue. City stopped by and didn't have a temp solution really either. Mention of foam and/or sandbags. Right now I'm just trying to prove to them that it's obviously where it's coming in at. Probably going to use a water hose to prove it
    – JGood
    Jan 25, 2023 at 22:39
  • Accepted your solution and added my own to main part of post. Thanks for answering!
    – JGood
    Jan 27, 2023 at 19:10

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