Does this CMU block wall on pool need rebar?

Question

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.

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.

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.

Answer 1

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.