So I'm in the process of remodeling my backyard. One of the things I wanted to do was build a wall similar to the first picture I included (with the stacked stone). The red arrows point at the wall.

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I had someone come out and build the small wall (it's 28" high from where the pool already ended (where the the white ends in the pictures below and it's 18 feet long) and will be putting stacked stone on it (real stone, so it's heavy). The stacked stone will go from just above the water level where the red tile ends in the pictures below and cover the whole front and sides of the wall.

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My question is, should this small wall have rebar in it? I'm not sure the guy who built it put any reinforcement into the wall and it is a very long wall. Should he have drilled into the part of the pool already there and put rebar into it? (or is that dangerous/could cause leaks in the pool and crack the side) Or is rebar in just the new sections fine? Or does it not need rebar? The wall is obviously not very tall, but my concern is the stacked stone is super heavy and it's all on the front part of the wall, could it topple over without rebar? Should I tear it down and start all over again?

Or am I fine because it's so short? Any help would be greatly appreciated.

I live in the Phoenix metro area in AZ.

2 Answers 2


Do you need rebar? Yes. Concrete and masonry do not withstand tension. Tension is absorbed by reinforcing. Think of a diving board. When you stand on it, it bends. Same with your wall. When there is a stress put on your wall, it bends. On one side it’s in compression, which is taken by the masonry. On the other side it is in tension and needs rebar.

There are many stresses on your wall, 1) A person (or persons) leaning against the wall, 2) seismic activity, 3) wind loads.

1) You’ve created a “Guard” as defined by the ICC Code. Guards are required to withstand 200 lbs. applied to the top of the wall.

Your wall is only 26” high and you’ve designed “an attractive nuisance “. Who doesn’t want to jump off the wall into the pool? That force on the wall when you jump forward could push the wall over.

2) Arizona is seismically active. (Northern Arizona is really bad, but Phoenix is active.) Heavy materials are harder to control in earthquakes.

3) Wind is probably not the governing factor.

I wouldn’t have any beer parties where a bunch of drunken friends start jumping off the wall or where they could be “horsing around” and stumble into the wall, until it’s checked out.

Btw, not all walls need rebar. Mass or gravity walls resist stress by shear weight. That’s possible, but highly unlikely and are usually battered (thicker at the bottom than at the top).

You may need buttresses every 4’ to 6’ on center along the length of wall for added support.

  • this is an awesome response so thank you for that. So would I be better off just starting over and knocking that wall down? My concern is obviously it tipping forward into the pool while someone is in there. The current white part that was already part of the pool is actuallly CMU block that was filled in with concrete, to add a new wall on top of it would you drill anchors into this CMU block and use that to then attach a base plate and the rebar to that?
    – Joel L
    Commented Feb 19, 2018 at 22:38
  • 1
    First, I’d confirm there are no reinforcing. Then I’d contact a “local” architect or structural engineer, (not a civil engineer. ) I’m not sure of the purpose of the wall, id reassess that too. I’d have a professional review it.
    – Lee Sam
    Commented Feb 19, 2018 at 23:58
  • 1
    I would be more concerned about the footing, the mix could have fiberglass as a reinforcement. Or even a piece of rebar it is decorative not structural. Unless you plan on putting some bolders on the wall if it has a good footing it will hold the weight of some rock glued on it. I would be more conerened about the Styrofoam pulling loose if heavy stones are attached to that.
    – Ed Beal
    Commented Feb 20, 2018 at 0:02
  • There is no reinforcement, the blocks on the side and middle are filled with mortar but other than that nothing really. What do you mean when you say more concerned about the footing? You mean the connection from the new block to the white part? And which styrofoam are you referring to?
    – Joel L
    Commented Feb 20, 2018 at 0:30

I also live in the Phoenix area. As far as it being seismically active here, it is probably the last thing I would worry about.

If the cells in the block have been filled with mortar, the only possible concern I would have is how it was attached to the existing foundation. If they used even a couple of rebar dowels to pin it in place, it will be fine.

Test it by pushing against it as hard as you can. If you don't get any movement, I'd say its going to be fine. My neighbor has a similar wall with empty cells that has been there for 10 years. Tearing it out without damaging the pool is not going to be a simple task. I don't imagine that even if it does fail, it will fail suddenly - it will start being wobbly long before it fails.

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