How do you build a water tight container out of concrete?

Question

I need help building a large cement "trough" of sorts which will hold water for a very large papyrus plant that is currently taking over my pond. The trough will be approximately 6 feet long by 3 feet wide by about 3 feet tall. I have purchased cement and already have chicken wire for support. My question is what is the best way to get it to retain water without using a product which will be detrimental to my papyrus. Is this something I even need to worry about since I have plants that I water daily right next to the location this will go to and I can just top off what is missing every morning when I water. Any input is welcome and appreciated! Thanks!

Answer 1

Once you have the trough built, you can use a waterproofing paint to seal the concrete. I had a birdbath that developed a leak and wouldn't hold water. I put one coat of the waterproofing paint on it and it has held water ever since. It was made by a company called UGLI.

Answer 2

You need to make concrete "forms" out of wood (and nails) in the shape of your trough, bottom and everything (a flat board is the bottom, then the sides formed in both sides of wood. I suggest you pour the sides, let them firm up and cure, remove the inside forms and then pour the bottom and smooth it over. Once the concrete is cured, you can slap some swimming pool paint (concrete paint) on it and that'll make it waterproof.

Instead of all this mess, why dont you just relocate the plant? Dig it up, place it in a large pot with plenty of dirt and put it somewhere else, or back by the pond.

Answer 3

If you build the trough in pieces you can hold it together at the seams with adhesive made for landscape blocks. I don't know if it would be considered environmentally safe for plants. However, if you are worried it might hurt the plants you could use a plastic liner like they use for ponds. I used it to seal the concrete blocks I used to build my retainer walls with and the dirt is up next to the blocks so my plants don't come in direct contact with it. It hasn't hurt them.

Answer 4

I think it would work like terra cotta pots where the water will evaporate out some if not sealed. The previous poster had good suggestions. Maybe some rebar in there too since it is so large.