How Do You Build a Gunite Pool Step by Step?

Construction follows seven distinct phases from dirt to water

Building a concrete pool takes between six and twelve weeks under normal conditions. Weather, local permit timelines, and soil conditions can extend that schedule. Following a strict order prevents you from tearing out finished work to fix buried lines.

1. Plans, permits, and excavation

Engineers draw structural plans based on your yard's soil type and ground slope. Your local municipal building department must approve these drawings before any digging begins. Excavators then dig the hole, carving out the deep end, shallow end, and bench shelves.

Crews dig the hole slightly larger than your pool's planned interior dimensions. This extra space gives workers room to build wooden support forms and lay plumbing lines behind the walls. Dump trucks haul away tons of soil unless you plan to use the dirt for grading around your property.

2. Wooden framing and steel rebar installation

Framers place wooden forms around the perimeter to mark the pool edge, called the bond beam. Workers place wood stakes and flexible plywood to guide the shape of curves, stairs, and sun ledges.

Next comes rebar (steel reinforcing rods tied into a cage to hold the concrete). Workers bend and tie steel bars in a crisscross grid across the entire floor and walls. Concrete spacer blocks, called dobies, lift the steel grid a few inches off the dirt. This clearance ensures the concrete completely surrounds the steel cage once sprayed.

3. Rough plumbing and electrical bonding

Rough plumbing (underground PVC pipes laid before concrete is sprayed) goes in before the shell is formed. Plumbers install the main drains at the deepest point, skimmer boxes along the top edge, and return lines that push clean water back into the pool.

Plumbers cap every pipe and pump them full of air or water to monitor pressure gauges. The lines must stay under pressure during the concrete pour to show instantly if a pipe gets punctured. Electricians also wrap bare copper wire around the entire steel cage. This bonding wire connects to the pump equipment pad so stray electrical currents flow safely into the ground rather than the water. You can see how to ground a pool pump safely to understand how proper equipment pad grounding protects swimmers.

4. Spraying and shaping the gunite shell

Spraying the gunite shell requires specialized heavy machinery and a skilled crew. Gunite is a dry blend of sand and Portland cement pushed through a hose with high-pressure air. The nozzle operator adds water right at the tip as the mixture shoots out against the dirt and rebar.

Finishers use hand trowels, screed boards, and straight edges to carve out smooth steps, straight walls, and curved coves. The concrete hardens within hours, creating a thick, solid rock bowl that forms the pool shell.

5. Water curing the raw shell

Fresh gunite does not dry to get hard; it cures through a chemical reaction between water and cement particles. The pool shell must remain wet for several weeks to reach its intended strength.

You or your contractor must spray the shell with a garden hose multiple times each day. Skipping this step dries the surface too quickly, which leads to spiderweb cracks and brittle concrete.

6. Coping, waterline tile, and pool deck

Once the concrete gains initial strength, masons install coping stones around the top rim of the pool. Coping provides a clean, safe edge to hold onto and separates the pool shell from the surrounding patio.

Masons set a band of waterproof tile along the waterline (the tile border where water meets the pool wall). This glazed tile makes it easy to wipe away waterlines and oils that would otherwise stain bare concrete. Contractors then pour the concrete pool deck or lay pavers around the perimeter.

7. Interior plaster, water fill, and startup

The final stage is applying plaster (a smooth, waterproof top layer applied over the rough shell). Plaster crews trowel a waterproof mix of white cement, marble dust, or pebble aggregate over the entire interior.

Water must fill the pool immediately after plastering without stopping. If the hose stops before the pool is full, the plaster can form a permanent ring mark at the water level. After the pool fills, you balance the water chemistry, start the circulation equipment, and follow how to open an inground pool step by step to protect your fresh plaster finish during its first month.

Gunite differs from shotcrete in how water mixes

Many people use the words gunite and shotcrete interchangeably, but the two methods mix concrete differently. Gunite uses a dry process. Dry cement and sand travel through a hose by air pressure, and the nozzle operator mixes water into the stream right as it leaves the nozzle tip.

Shotcrete uses a wet process. The concrete arrives pre-mixed in a standard concrete mixer truck with water already blended in. A concrete pump pushes the wet sludge through a hose, and compressed air at the nozzle blasts it onto the pool walls.

Poured concrete is completely different from both sprayed options. Poured concrete requires rigid wooden forms on both the front and back of every wall, with wet mix dumped between the forms. Building double forms for curves and custom stairs takes immense labor, which makes poured concrete rare for residential pools.

Gunite remains the most popular choice for custom pools because it allows total flexibility. The crew can pause work without concrete setting inside a truck drum. The nozzle operator can also adjust water volume on the fly to build steep walls and custom benches without forms sagging.

Wetting the shell daily prevents weak brittle concrete

Concrete does not reach maximum strength by drying out in the sun. It gains strength through hydration, a continuous chemical reaction where cement particles bind tightly with water molecules. If water evaporates from the concrete too fast, the reaction stops and leaves the shell brittle.

Hydration generates internal heat that causes the concrete to contract as it cools. Daily watering cools the concrete and replaces lost surface moisture. Follow this curing routine after the crew sprays the pool shell:

• Start soaking the shell the morning after application, as soon as the concrete surface resists light water pressure without washing away sand.
• Spray all interior surfaces two to three times per day, giving extra attention to sunny walls and shallow shelves that dry out fast.
• Use a hose nozzle with a gentle shower setting so you do not gouge soft spots or wash away fine cement paste.
• Continue this soaking routine for a minimum of seven to fourteen days before stopping.
• Allow standing water to collect in the deep end, which helps hydrate the floor slab from the bottom up.

Proper curing takes about 28 days for concrete to reach its full structural strength. You do not need to water it for all four weeks, but the first ten days are critical. Keeping the shell wet prevents shrinkage cracks and provides a dense base for your final plaster coat.

Managing subcontractors saves money but carries real risk

Acting as your own general contractor, often called an owner-builder, can save you 15 to 25 percent on construction markups. But managing the job yourself means taking on all financial, legal, and structural responsibility for the build.

A turnkey pool contractor handles engineering stamps, pulls permits, schedules trades, and warranties the entire structure. If a pipe leaks behind the gunite or the shell cracks, the licensed builder must fix the problem. You pay a premium for this security, but it protects your investment from expensive subcontractor disputes.

An owner-builder must hire separate crews for excavation, steel tying, plumbing, gunite shooting, tile work, and plastering. Subcontractors often prioritize their regular builder clients over individual homeowners, which can lead to long delays between phases. If one trade damages another trade's work, such as a gunite crew cracking a PVC line, you must settle the dispute yourself.

Choose the turnkey route if you work full-time or have never managed complex building projects. Consider the owner-builder route only if you understand local building codes, have time to supervise work daily, and feel comfortable coordinating heavy machinery and trades on your property.

Common building mistakes cause costly leaks and cracked shells

Small oversights during early construction phases can lead to structural failures that cost thousands of dollars to fix. Understanding these common errors helps you inspect the work before concrete locks everything in place.

Failing to support rebar with dobies is one of the most frequent structural mistakes. If the steel cage rests directly on the dirt floor, soil moisture will rust the steel bars over time. Rusted rebar expands, cracking the concrete from the inside out in a failure known as spalling. Ensure the steel grid sits at least two to three inches above the dirt on concrete blocks.

Skipping a continuous pressure check on the rough plumbing can ruin a project. Heavy equipment, rebar crews, and gunite rebound can crack a buried PVC pipe without anyone noticing. Keep pressure gauges on all water lines at 35 pounds per square inch throughout the build. If a gauge drops, stop the crew and find the leak before shooting concrete.

Inadequate soil compaction beneath the pool floor causes uneven settling. Loose fill dirt shifts once the pool holds thousands of gallons of heavy water, causing the concrete bowl to crack down the middle. Soils with high clay content expand and contract with rain, requiring deeper footings or specialized gravel bases to protect the shell.

Shadowing is a hidden flaw that happens when a gunite nozzle operator shoots concrete at the wrong angle. If the spray does not blow directly behind the rebar, hollow sand pockets form on the backside of the steel. These uncompacted voids leave weak spots where water can seep through the pool shell.

Rushing the plaster application before the gunite cures can ruin the finish. Gunite releases alkali and moisture as it cures. Applying plaster too soon can cause blistering, discoloration, or delamination, where the plaster separates from the concrete wall. Give the shell adequate curing time before applying decorative finishes.