1

I want to build up a short dam of maybe half an inch in height, to control where water is flowing. The water flows as a small, steady trickle. Right now it fans across a large-ish area. I'd like to concentrate its flow to a specific area.

What kind of cement or mortar should I use to direct the flow? I was thinking of hydraulic cement, but I wanted to check first. The area is wet. I want to make sure the new cement sticks to the existing thin cement floor in the cellar.

I also have some quick set mortar powder on hand, as well as some resurfacing cement. If none of the products I have on hand is the right thing, I can buy something new.

I don't care about the aesthetics in this case.

  • why not just slope the floor gently? – Solar Mike May 13 at 5:08
  • @SolarMike - There's already a slope. // I don't want to tear up the floor and reconfigure the whole contour, and I don't want to resurface the whole thing. (I'm not sure if that's what you were suggesting.) – aparente001 May 13 at 5:11
  • I usually find new cement sticks well where it is not wanted, but otherwise does not stick... IMHO adding a 1/2" ridge is just a trip hazard, but your choice, which is why I suggested a slope as that detail was lacking in your question. – Solar Mike May 13 at 5:16
  • @SolarMike - Sorry I didn't mention the slope. At any rate, the location would not create a tripping hazard. It's under some stairs. What do you think about the hydraulic cement? I watched videos about it, and read the instructions. The standard way to use it is to plug up a hole. My situation is different. – aparente001 May 13 at 5:18
3

Hydraulic cement sticks to wet fine, but you may need to abrade the surface to get to clean concrete, as it won't like a greasy, dirty or otherwise befouled surface.

However, what I would actually do (and have actually done) to direct water on a concrete floor is to use a diamond saw to cut a small channel into the surface - much neater and tidier - also easier to walk or roll over. And much less wet area.

  • Thank you, I'll try putting some leftover siding cleaner on it and scrubbing, and then rinse well. Unfortunately I don't have a diamond saw. – aparente001 May 13 at 14:09
  • You might be surprised how affordable a one-day rental is, if you don't get the absurdly large one. Depends on your local tool rental outlet, but they are not hard to come by. – Ecnerwal May 13 at 14:14
  • Thanks for the encouragement. If my first primitive attempt doesn't turn out, I'll try the diamond saw rental idea. – aparente001 May 13 at 14:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.