Questions about pouring concrete on a ledge -- how to support or make a "form".....?

[Mmathis]

I hope that makes sense.....

Doing some renovations to the pond sides and am installing a post-construction collar out of cinder block. We have 1) clay "soil" and 2) a high water table which has caused some slipping to the walls in areas where the soil is really bad.

I did a trial section yesterday afternoon and it went pretty smoothly. What I did was dig down into the rock ledge 8" to accommodate the height of the cinder block [partially into the berm, as well].

I was just curious about pouring concrete instead of using the cinder block, but since the rock ledge [and by "rock ledge," I mean the ledge where the rocks will go that hide liner] only has one side -- the other side is the pond side -- how in the heck to you provide for the wall to support and contain the concrete?

 

[dieselplower]

Wood

 

[Tula]

I think you make a wood form. Have you ever seen a side walk laid or a patio? They make wood forms first and then pour the concrete. Once set, the wood is removed.

 

[Mmathis]

But what would you attach the wood to?

 

[dieselplower]

It seems like you would have to make a frame that rested on the pond bottom or something like that. Vertical boards to get it to the right height

 

[Mmathis]

It seems like you would have to make a frame that rested on the pond bottom or something like that. Vertical boards to get it to the right height

Oh, OK, I see.

 

[dieselplower]

You could also run boards across the top of the pond and attach the form boards to that...

 

[Mmathis]

Bend a section of lath mesh into an "L" shape, and hold it in place with the rebar. What if you used quick-set concrete, so that you could do it in sections and put "hand" pressure to keep the lath mesh in place and not bulge until it was stiff enough to hold its shape....? Would the concrete set fast enough for this (picture) to work?

My pictures are not to scale, but my purpose is to retro-fit a collar around the pond edge. Just not sure which is easier at this point: trying to self-pour concrete (I would rent a mixer) or use cinder block.....

 

[snoozer]

How many feet are you going to be doing? I think it would be much easier to use the concrete block, ready made, easy to put into place. less messy and I think they are easier than hauling and mixing 60 pound bags of concrete. If you decide on concrete, you can make a wood form to contain it. The wood needs to be held in place with stakes. The stakes would be on the side opposite where the concrete would be poured and driven into the ground. You would need to be sure your stakes were driven deep enough to hold the form stable to contain the concrete. If the form shifts, the concrete would run under your liner which would be a bad thing. The form lumber would be held to the stakes with nails You would also need to oil the wood form to keep the concrete from sticking to it. Best of luck.

 

[RobAmy]

I personally would use the cider block and then fill them with the concrete, the block will be your form and then it will be solid. They make what is called bond beam and put the rebar laying into the concrete. You may want to drill holes and put rebar like in your drawing down into the ground.