Can I cast my own concrete retaining wall?

[Tony Sinclair]

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.

[SQLit]

Forming and reddy mix is the way to go. First you need good base to put the blocks on. If your looking for an electric mixer I highly recommend the Gibson.

Small enough to go through a door way but stable. I did some concrete work inside with one recently. I see that the price took a jump. I paid just over $300 for mine delivered.

Trying to do an retaining wall over a couple of years seems lame to me. I would be interested in getting the ground stabilized. If you doing this on the fence line maybe your neighbor would be interested in pay for part. After all he would be getting a wall out of the deal. I certainly would ask.

[Bob]

You'll have to pour a foundation, or it will fall over.

[Bob]

Maybe his neighbor would want him to hire someone so it doesn't fall and hurt some kid when they are playing on it.

[Freckles]

Have you ever considered a fero-cement fence?

[EXT]

Mixing cement and sand together does not make concrete. You will need lots of gravel. You make concrete with one part Portland Cement, two parts sand (it must be clean, coarse sand to make it work) and three parts gravel. You will find making it yourself very tiring, will take a lot of materials and have to mix lots of batches. For example, a wall 100 feet long x 1 foot thick x 5 feet high (it really should go deeper than 1 foot into the ground, depending on your frost situation and soil stability) will take 500 cubic feet. Your mixer may make 1, 1 1/2 or 2 cubic feet at a time, this will take

500 to 250 batches to make your wall. When you figure the work, cost and time involved, plus buying re-inforcing steel, the retaining wall blocks will look good.

Check out other brands of retaining wall blocks, some are good for 4 feet high and more and are not that expensive. Don't look at the home center to buy them, look in the yellow pages for concrete products and buy direct from the manufacturer.

[Edwin Pawlowski]

Couple of thing to do it right. You need a footing. Depending on local regulation, that may be 12" to 48" so check that out. Footings are easy, pretty much filling up a big hole and leveling the top. I'd use a reddi mix truck for that so it can be done in one pour.

If you want to mix yourself, you can probably find a used mixer at reasonable cost.

Check local regulations. You don't want the building inspector make you tear it out for some silly reason that you missed.

In addition tot he sand, you need some gravel. There are books and charts to give you the right proportions for the mix.

I have heard of people doing what you intend to do and though it took time, it can be done. Lots of work hauling the sand and gravel though.

[timbirr]

The problem with your project may be your sand. If you are thinking of using "beach sand" for the concrete, it could well have a high level of salt. Too much salt in your cement and you get nothing concrete.

I suppose you could check and see what the salt level is in your sand, and then wash it somehow to get rid of the salt if indeed there is any problem.....(and don't use seawater HAHA).

Or buy sand from a contractor.....

[Joseph Meehan]

...

I suggest you need a local professional to take a look at your lot and plan. Retaining walls, especially when built on unstable ground tend to be unstable. You need a good well engineered design first. You will also likely need to meet some sort of local zoning and building requirements as well as need permit, especially since it is near the property line.

[Tony Sinclair]

I didn't even know I needed a mixer. I thought that if the form is only 1 foot deep, I can mix it right in the form with a metal rod. Is that stupid?

[Tony Sinclair]

I thought a foundation was only necessary when the soil was susceptible to cracking or freezing. Neither is the case here. Pure sand, and it very rarely gets below freezing. Or above 75, for that matter. Does that make any difference?

[Tony Sinclair]

No, and there's a very good reason for that. I have never heard the term before. I'll look it up, but it sounds expensive.

[Tony Sinclair]

Thanks, I will do that. One problem, though, is that I am in a very small town, and the nearest city of any size is over an hour away, so the delivery charges may be prohibitive.

[Tony Sinclair]

Thanks, I will check into it. There is no room for a truck to get back there, though. Can they extend their chutes 100 feet?

As I said to another person, I didn't know I needed a mixer. Is it impossible to mix concrete by hand, even in very small batches? I am pretty strong.

Hadn't even occurred to me. Thank you.

I thought I read that you can just use sand. Guess I have to read some more.

The sand is already right there. If I need gravel, that will be a problem, but not a big one. I can have them dump some in front of my house, and move it back one block's worth at a time.

Thanks to everyone for the responses.

[Tony Sinclair]

Yes, I assume it's beach sand, since I'm in a coastal dune area. Thanks for the tip, I will do some reading on this.

[Tony Sinclair]

Yes, it will be right on the property line, so I need to see about a permit. As for the stability, I think the ground is pretty stable. I live in a double wide mobile home, and they are pretty sensitive to the ground shifting. No problems in seven years so far. As I said in another post, the climate is moderate and there is zero clay in the soil.

[Bob]

[Bill Kearney]

Find a better source. Get them in bulk from a block supplier, not home depot.

Any number of interlocking systems can span heights in excess of 30' so your tiny wall shouldn't be a problem.

But more importantly you should check local code requirements FIRST. You don't want to put up something that doesn't pass local codes.

Before you go putting something on a property line you want to be SURE about it. Make a mistake and put it on their side of the line and you could get stuck with paying for whatever methods THEY might choose to have it removed! Put it too far on your side and you potentially set up a future boundary/use issue.

Best to be CERTAIN what the law requires. If it's on the property line have a SURVEY done to make sure you're putting it in exactly the right place.

Oh lordy, how shitty looking do you want this to be? Creating consistent concrete, especially THAT much, is not a DIY job, especially not by trying to use your own sand.

Does "slowly make an enemy of your neighbor" sound like a reason not to do it? If it's in sight of the neighbor think about how annoying it'd be to have a half-constructed wall being an on-going eyesore.

No. Especially not from beach sand.

Well, it's not "stupid" but it's not smart either. Look into other block products. Then look at planning a decent schedule for getting the job done. Get a backhoe, dig a trench for the foundation, have a load of concrete or other base material trucked in and get the base layer laid all at once. That way you'll have a nice level base on which to lay the block courses. Laying interlocking block systems actually goes pretty quickly. Since you'll be getting then in bulk, try to have them drop the palettes of blocks

[buffalobill]

your back will be ruined in a two days, and you'll be left with a noisy machine and truckloads of concrete mix nobody would touch. alternatively your small home improvement loan payments and the beautifully professionally installed concrete on a safe inspected foundation will be painless and last forever. your post is entertaining and ambitious. your project despite what old neighbors may have constructed nearby may not presently be proper for your area, check with the building inspector at your permit office and other offices managing costal areas. whether any wall is allowed and to how many feet of the property line and to what altitude is in your local ordinances. recheck your survey to see how far the legal property line goes, and the permit office will tell you how far inside it you must build. your sand especially when wet behaves very differently from our buffalo ny soil. a homemade improper retaining wall may have a negative effect on your property value and neighbor's view. perform a written petition of your neighbors within the specified numbers of feet from your property before you apply for any zoning variance.

[Edwin Pawlowski]

Yes.

There is no way you will mix it in the form. Mix it in a wheelbarrow and then dump it. Or in a trough and shovel it into the form.

Before you invest heavily into this, make a small form. Buy a bag of the pre-mixed stuff and give it a go. Once you realized the weight of it and the amount of turning over needed, you will start looking for a better method.