Thinking of skipping rebar for a small plunge pool, dumb idea?

K

Kevin Marsh

Member
So I’m building a small plunge pool, around 8x8 feet, and I keep going back and forth on the whole rebar thing. Some people say it’s a must, while others argue that for a tiny pool like this, a compacted base and fibre mesh are enough. Anyone here actually skip rebar and live to tell the tale?
 
I built a small plunge pool about the same size and debated skipping rebar too. Ended up using a light rebar grid anyway after talking to a local builder. He said even small pools can crack from shifting soil or freeze/thaw cycles if they’re not reinforced. Fiber mesh helps, but it’s not a full replacement. Rebar might feel like overkill, but once the concrete's in, there’s no going back. I’d say play it safe unless you're okay with patching later.
 
I actually skipped rebar on my 9x9 plunge pool last year and just used fiber mesh in a thick slab over a well-compacted base. So far, no cracks and it’s held up fine, but I live in a very stable, warm climate with no freeze issues. That said, I poured thicker than usual and added extra control joints. It can work, but it’s definitely a calculated risk. If you’re in an area with shifting soil or heavy rains, I’d probably go with rebar just for peace of mind.
 
I’ve tried building a small pool without rebar before, but after chatting with some more experienced friends, I decided to stick with rebar. Even though it’s a small pool, I feel better with the structure being more solid. If you’re looking to save costs, it’s something to consider, but make sure to think about the ground conditions and weather too!
 
Interesting debate here! I was actually thinking of skipping the rebar too, but after hearing all the opinions, I think I’ll stick with it. Even though it’s a small plunge pool, it’s reassuring to know that rebar can add a lot more long-term stability. Plus, I’ve heard it’s pretty difficult to patch up once things start cracking. Has anyone tried using a lighter gauge rebar for smaller projects like this?
 
Interesting perspectives, everyone! If you're still on the fence about the rebar, maybe consider using it for extra reinforcement around the edges where the pool will face the most pressure. It could be an easy compromise helping with durability while still saving a bit on the overall material costs.
 
I had the same dilemma about using rebar for my small pool. Initially, I thought I could skip it and just use a solid base with fiber material. After talking to a few builders, I decided to go with rebar. They explained that even for a small pool, rebar helps prevent cracks due to shifting soil or temperature changes. Even though it cost a bit more, I felt much more confident knowing that the structure would be more stable and last longer.
 
I don’t think it’s a dumb idea, but it’s one of those choices that only looks smart if everything goes perfectly long term. Concrete doesn’t usually fail right away, it fails slowly, after seasons of settling, moisture movement, or a random stress you didn’t plan for.

What pushed me toward rebar on a small project was realizing how little control you actually have once it’s poured. You can do a great base, nail the mix, and still get one odd crack years later from something as simple as a wet season or nearby ground movement. Rebar doesn’t stop cracks entirely, but it keeps them from turning into structural headaches.

That said, I get why people skip it: cost, effort, and the feeling that an 8x8 pool isn’t exactly a bridge deck. If you’re already digging, forming, and pouring, though, adding a basic rebar layout is one of those “cheap insurance” steps. You’ll probably never notice the benefit, and that’s kind of the point.

If nothing else, think about future-you. Rebar is annoying once. Repairs are annoying forever.
 
I’ve seen a few small plunge pools skip rebar and survive, but almost all of them ended up with small cracks or minor movement over time. From what I’ve seen, an 8x8 pool can work with a solid base and fiber mesh, but rebar is what gives long-term peace of mind when the ground shifts or seasons change, it feels like overkill at first but usually pays off later.
 
Honestly, small size doesn’t always mean small risk. I’ve seen similar builds look fine at first, then hairline cracks show up after a few seasons. For me, if you’re already this far, adding reinforcement gives peace of mind, especially if your ground conditions aren’t perfectly stable.
 
I wouldn’t call it dumb, but I’d call it optimistic.

An 8x8 plunge pool still holds a surprising amount of weight once it’s full. Water is about 8.3 pounds per gallon, and even a small cube of water adds up fast. That load is constantly pushing outward on the walls and downward on the slab. Fiber mesh is great for controlling surface cracking, but it doesn’t really replace steel when it comes to handling tensile stress from soil movement.

What a lot of people overlook is differential settling. Your base might be perfectly compacted, but if one corner gets a little more moisture over time or the soil shrinks and swells, that’s where stress concentrates. Rebar doesn’t prevent cracks completely, but it helps keep them tight and structural instead of turning into shifting or bowing.

If you’re in a warm, stable climate with sandy soil and zero freeze-thaw, you might get away with it. But if you have clay, heavy rain, or seasonal temp swings, that’s when skipping steel tends to show up a couple years later.

For the cost difference on something that size, rebar is usually cheap insurance. Once it’s poured, there’s no redo without serious pain. If it were me, I’d rather overbuild a small pool than underbuild it and spend the next five summers staring at a crack wondering if it’s growing.
 
I’d lean toward using it. Even with a small plunge pool, the forces involved are bigger than they look once it’s full of water.

An 8x8 pool might seem tiny, but when you start thinking about the weight of the water and the pressure pushing against the walls, it adds up fast. Concrete is strong in compression but not great with tension, so when the soil shifts a little or the ground gets uneven moisture, that’s where cracks tend to start. Fiber mesh helps control surface cracking, but it doesn’t really replace steel reinforcement for structural strength.

Another thing people forget is long term ground movement. Even if your base is compacted perfectly today, soil changes over seasons. Rain, drying, and temperature swings can cause small shifts that put stress on the shell. Rebar basically ties the concrete together so if a crack forms, it stays small instead of spreading or separating.

On a project that size, the extra material and labor for a simple rebar grid usually isn’t huge compared to the overall build cost. But once the concrete is poured, there’s no easy way to go back and add it.

So it’s not that skipping rebar is impossible, people do get away with it in very stable conditions. It’s just one of those things that’s cheap insurance while everything is still open.
 
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