Hi,

I'm new here just signed up looking for some help with my new fish keeping hobby I'm taking up.

I'm building my own pond and so far everything has gone smoothly.

I've hit a brick wall with building the fountain.

So far I've built up the walls of my fountain and it will be lined and I want it to overflow over the side.

I have several granite bricks cemented in place and I want to put a slab sticking out at the very top where it overflows so the water won't trickle down the side of he bricks and instead falls a bit out from the wall.

My issue is i want to make 100% sure the cement mix I use is strong enough as the slab is heavy, the slab is 60cm and the bricks are only 15cm wide.

So I only have 15cm of room to stick the slab to and 45cm sticking out.

Hope I've explained this well enough if anyone can advise I'd appreciate it. I dont want the slab falling into the pond and ripping the liner.

Pictures speak a thousand words. (You know what you mean, sorry I am not sure)

Also are you aware you can not use neat / untreated sand / cement in a fish pond? it will kill the fish.
You have to "seal" it with a pond sealer OR wait till it sets and soak it on its own and repeat, and repeat, and repeat. Sealing it is easier.

Yeah no cement is in the pond this is a pond fountain that's lined. Thepond is also lined.

Imagine just a brick wall with house bricks they are only 15mm wide and I want to stick a slab on the top of the brick sticking out from the wall.

Drawing then if no picture, i really am trying to help. Cement does not need to be in the pond, water touching cement then running into the pond can also kill the fish, that's why you don't often see any "brick" fountains in ponds. I am also wondering how the water will flow?
I am guessing you want it to flow along this slab? (It might do, but will probably run off the sides) and what is this slab made from?
Like I said a drawing really would be appreciated, doesn't have to be a work of art, draw it on paper, take a picture and post that. (its what i have done)

Hello.

Cement is strong enough if you apply enough of it and know the physics. The wall will also have to be strong enough.

Also if you use cement, understand that cement needs to be "cured" before adding fish or the fish will die!!!!!.
Google "Curing Cement" for more details.
Why? ---- Simple Explanation: Cement when contact with water will "leak cement" which makes the pH rocket to a toxic level for most aquatic creatures. After in contact with water for a while (4-6 weeks), they got cured and don't do this anymore. But then you need to completely change your water in the pond completely.

Alternatively.... I've never thought about doing this outdoor.... but you can use foam!!!!!
Yes! Foam is lighter and comes with many color, you can even paint them. You can attach small rocks to them or woods. Or use dried and crush coconut shell to make it looks natural.
Google "Paludarium" or something like that, I forgot I it spell. Most of the time people use foam to build rocky walls that look very realistic but pretty light!!!

And like others have said.... we really need visual image to understand what you said best :)