After weeks of digging, plumbing, and tying steel, this is the day your backyard finally stops looking like a construction site and starts looking like a pool. The crew shows up, runs a hose into the hole, and sprays concrete over the whole thing. In a day or two, the shape you picked out months ago is suddenly real and solid.
It’s not the flashiest step. It’s grey, it’s loud, and there’s no water in sight. But there’s a good reason the concrete gets shot instead of poured, a difference between the two methods worth knowing, and one part of this stage you can actually influence. Here’s the whole thing in plain English.
Key Takeaways
- Pools are shot, not poured. Concrete sprayed at high speed packs in dense and sticks to the vertical, curved walls that pouring could never handle.
- Shotcrete and gunite are cousins. Both are sprayed concrete; the only real difference is whether the water is mixed in early or added at the nozzle.
- The crew matters more than the method. A skilled team and careful technique beat any debate over which mix is “better.”
- Curing is the step that counts. The shell gains its strength over about 28 days, and keeping it wet early is what prevents cracks.
- You’ll have a job to do. Your project manager will ask you to spray the shell with a hose for the first week, and you genuinely can’t overdo it.
Why Pools Are Shot, Not Poured
Think about the last sidewalk you saw being made. Wet concrete gets dumped into flat wooden forms and smoothed over. That works great for something flat and horizontal. Now picture pouring that same soupy concrete onto the curved, near-vertical walls of a pool. It would just slump and slide straight to the bottom.
That’s why pool shells are sprayed instead. The concrete is blasted out of a hose at high velocity, which does two things at once: it packs the material down so densely there are no air pockets, and it makes each pass bond tightly to the steel and to the concrete already on the wall. The result is one continuous shell with no weak seams, which is exactly what you want holding back tons of water.
- Density. High-speed impact compacts the concrete far better than pouring ever could.
- No cold joints. Sprayed concrete fuses to itself, so there are no weak seams where layers meet.
Shotcrete vs Gunite: What’s the Difference?
Here’s where the two words your project manager keeps using come in. Both shotcrete and gunite are sprayed concrete, and people often use the terms loosely. The only real difference is when the water meets the mix:
- Shotcrete (wet-mix). Arrives premixed and wet in a truck, ready to pump and spray right away.
- Gunite (dry-mix). Shows up dry, with water added at the tip by the operator (the “nozzleman”) as it’s sprayed.
- Many backyard pools use gunite. Adding water at the nozzle gives the operator finer control for custom curves, steps, and shelves.
Don’t get too tangled up in which one is “better,” though. Both make a strong, watertight pool when they’re done right. What actually decides the quality of your shell isn’t the mix; it’s the skill of the crew shooting it and how carefully it’s cured afterward.
What Shoot Day Actually Looks Like
Before anything is sprayed, the plumbing gets capped and pressure-tested, and an inspector usually signs off on the steel and plumbing, since all of it is about to disappear under concrete. Then the nozzleman goes to work, shooting the floor and walls while the rest of the crew carves, screeds, and trowels the wet concrete into its final shape. It’s fast and messy: expect overspray (called rebound) scattered around the yard, and expect to watch your pool’s real shape appear within a day or two.
The One Step You Can Actually Mess Up: Curing
Here’s the part most homeowners don’t see coming. Concrete doesn’t simply “dry” and harden; it cures through a slow chemical reaction called hydration, and that reaction needs water to keep going. A pool shell takes roughly 28 days to reach full strength, and the first week or so is the most important stretch of all.
If the surface dries out too fast, the reaction stalls and you’re left with weak, brittle concrete that’s prone to shrinkage cracks and leaks later. That’s why your project manager will hand you a garden hose and ask you to spray the shell several times a day for the first week. It feels odd to water a hole in your yard, but it’s doing real work, and as the pros like to say, you genuinely can’t overwater fresh gunite.
- Why it matters. Moisture keeps the concrete curing to full strength instead of drying out brittle.
- Your part. Spray the shell a few times a day for the first week or so, and more often in hot weather.
Quick tip: Set a phone reminder or put a sprinkler on a timer for the curing week. The shell can’t be overwatered, so erring on the side of too wet is always the safe bet.
Frequently Asked Questions
Almost. Both are concrete sprayed at high speed to form your pool’s shell. The only real difference is timing: shotcrete arrives premixed and wet in the truck, while gunite shows up dry and gets its water added at the nozzle. Many backyard pools use gunite.
Neither wins on paper. Both build a strong, watertight shell when they’re done right. What actually decides quality is the skill of the crew shooting it and how carefully the shell is cured, not which mix you pick.
The shell keeps gaining strength for about 28 days, but the first week matters most. Keeping it wet through that stretch is what prevents shrinkage cracks down the road.
Yes, and expect to be asked. No crew is coming by twice a day for a week, so watering the shell falls to you. Watering the fresh shell several times a day for the first week keeps the concrete curing to full strength instead of drying out brittle. As the pros say, you can’t overdo it.
Not yet. Shoot day gives your pool its concrete bones, but tile, coping, the plumbing finish, and the interior surface all still come next, plus the curing week. The shell is a big milestone, not the finish line.
The Bottom Line
Shoot day isn’t exciting. It’s grey and loud and over fairly quickly. But it’s the moment your pool gets its bones, and the curing that follows decides whether those bones stay strong for the next fifty years. It’s not the day you’ll photograph; it’s the day that makes all the pretty ones possible.
Building a pool? Ask your project manager, if you opt to work with one, how they handle the shell, whether they shoot gunite or shotcrete, and exactly what they’ll need from you during the curing week. A crew that takes curing seriously is a crew that’s building you a pool to last.