I live on the Oregon coast, and my lot is almost pure sand. It is about four feet above the lot next door, so I need a retaining wall to keep my sand from sliding into the neighbor's yard. When I first bought the place, there were some railroad ties there, but they are weathering away, so I need a more permanent solution. They are only two feet high and my lot slopes down from my house to the edge; I want to make a four foot wall so I can have a flat lot (I can get more sand).
Every conventional solution I've seen is too expensive for me. My property line is over 100' long, so buying concrete landscaping blocks at $2 apiece or so would cost thousands of dollars, plus most recommendations I've seen say they shouldn't be stacked much more than two feet high anyway.
I'm not much of a handyman by nature, but when I have to do something, and when I have good instructions, I can usually get it done.
My idea is to pour the concrete myself. I've never done it before, but I already have a lot full of sand, so I'm thinking that if I just do a few trial runs to figure out how much cement and water to mix with the sand, I can cast the blocks in place. It seems to me that all I would need would be a rectangular wooden form, and I could make it a lot bigger than a typical landscape block, because I wouldn't be lifting the blocks, I'd just put the form where I want it, shovel in the sand and cement, add water, and mix it up. When it is solid, I knock the form off and do the next block. I guess I would have to use a slightly smaller form for each layer, so the concrete doesn't run out of the bottom, but I can figure out how big to start at the bottom so that the top layers are still big enough.
I am thinking that if I did it this way, I could make a wall four feet high, because the blocks will be bigger and heavier than regular landscape blocks, and also I can gouge grooves in the top of the blocks I pour before they harden, so that the next layer fills the grooves and they lock together to resist sideways motion. I could even make the bottom layer with a wide flange that goes back toward my house, so the earth helps hold it in place.
I realize this would take a very long time, but I have time. If I just do a block or two a day after work, and maybe a dozen or so on weekends, maybe it will take five years, so what? At least the total cost will be less, and the cost will be spread out for as long as I want it.
So, I'm asking the experts here if this is feasible. Can a rookie learn to mix concrete good enough for this use fairly quickly? Is there something I don't know that makes it hard to cast a block on top of another block? If I make the blocks big, say 3'x2'x1' (lxwxh), and groove them the way I described, will they make a wall strong enough to hold back four feet of earth, or would I need some kind of additional measures? I know that I am not good enough to make a wall with mortared joints, but I was thinking I could imbed some kind of deadman anchors halfway up.
No need to be gentle with me. If this is just a stupid idea, feel free to say so, but please tell me *why* it's stupid. Thanks for any help.