Owning a swimming pool brings joy and relaxation, but it also comes with responsibilities—especially when it comes to maintenance and understanding your pool’s construction. One of the most essential questions homeowners often ask is: How do I know if my pool is gunite or concrete? This query becomes crucial when planning repairs, renovations, or even when scheduling long-term maintenance.
While both pool surfaces are concrete-based, the method of installation and the resulting structure differ significantly. Recognizing the type of pool you own ensures that you receive the most accurate advice and avoid expensive, unnecessary procedures. In this in-depth guide, we’ll explore the differences between gunite and concrete pools, how to visually inspect and test your pool, and the advantages of each type for further customization or care.
Understanding the Basics: What Are Gunite and Concrete Pools?
Before diving into how you can tell the two apart, it helps to understand what distinguishes gunite and concrete pools in the first place.
What Is a Gunite Pool?
Gunite is a dry-mix concrete that is combined with water at the nozzle during application. The material is pneumatically projected onto the pool structure quickly and precisely, allowing for greater flexibility in design and greater durability once fully cured. Gunite pools are renowned for their strength and adaptability to different shapes and styles—they’re often used for custom in-ground pools that follow unique landscaping contours.
What Is a Concrete Pool?
A concrete pool, sometimes referred to as a poured-in-place pool, typically involves mixing all concrete components (cement, sand, aggregate, and water) before pouring into a form around a rebar structure that serves as the skeleton of the pool. These pools are also in-ground and reinforced with rebar, but they gain their structure through a more traditional pouring method.
Differences Between Gunite and Concrete Pools
Even though both pool types use concrete, they are not the same. It’s common to confuse the two since they’re often discussed interchangeably—but key distinctions set them apart.
Construction Method
- Gunite: Sprayed through a hose onto a rebar framework. The dry materials are mixed with water at the point of application.
- Concrete: Entire mixture (including water) is pre-mixed before it’s poured into a mold set around the rebar structure.
Finish Options
Both types can accommodate a range of finishes—from plaster to tile—but gunite tends to offer more flexibility, especially with unique textures and integrations like water features.
Strength and Flexibility
Gunite, when properly applied, adheres more strongly to rebar and forms a denser shell. Concrete is heavier and requires more drying time, which can cause cracking if the ground shifts after installation.
Design Versatility
Gunite is ideal for custom builds—complex slopes, sharp curves, and multi-tiered pools. Poured concrete is more limited due to its heavy, wet form that needs molds and supports to keep its shape while drying.
How to Know If Your Pool is Gunite or Concrete: A Step-by-Step Guide
Now that we’ve explored the basic differences, let’s focus on how homeowners can determine the construction material of their swimming pool. This process involves visual inspection, tactile evaluation, and—if necessary—the help of professionals.
Step 1: Know When Your Pool Was Built
Understanding the estimated build date can offer helpful context.
- If your pool was installed before the early 1960s in America, it’s more likely steel or another early material. However, by the late 1960s and early 1970s, gunite usage gained traction for its performance and design diversity.
- Concrete in-ground pools were popular but required specialized equipment for pouring and drying, which limited construction flexibility.
Knowing whether your pool was constructed recently or decades ago may help guide the rest of your diagnosis.
Step 2: Visual Inspection of the Pool Structure
Look closely at the edges, walls, and the inside of the pool. Gunite and concrete have specific visual hallmarks:
1. Surface Texture:
- Gunite: Generally has a slightly rough or pebbled finish before plastering. You may notice a fine texture, especially in areas of wear or near joints.
- Concrete: Tends to have a smoother, more monolithic appearance after drying. It can be denser and heavier in appearance.
2. Curves and Contouring:
- Think about the geometry of your pool. Gunite allows for intricate shapes, like irregular curves or multi-angle steps.
- Concrete, while still moldable, usually results in pools with sharper, boxier edges due to the static molds and wet casting method.
Step 3: Check the Pool’s Edges and Steps
Gunite is often ideal for building custom details like integrated steps, spillways, or unique benches. If your pool has these features, particularly ones that aren’t uniform or symmetrical, it may indicate gunite usage.
Concrete-built steps, on the other hand, may appear to have a more solid and rigid form, often constructed from poured molds.
Step 4: Examine the Rebar Exposure
If sections of the rebar are exposed either at the edge of the pool or within a crack:
- Gunite pools tend to have rebar that looks irregular or bent, formed to the custom shaping of the pool.
- Concrete pools, in contrast, often have a rebar grid that appears more squared and uniform, following the formwork.
Step 5: Tap and Listen Test
While not foolproof, a tap test involves knocking a solid part of the pool wall either within or outside the water to hear the echo:
- Gunite typically produces a hollow, slightly higher-pitched sound when tapped.
- Concrete results in a denser, more muted, and lower-pitched echo.
Step 6: Contact Installation Records or the Previous Homeowner
One of the most reliable methods is checking records from the installation contractor, which often include materials used and construction details. If the original contract or renovation report isn’t available, consider:
- Reaching out to the previous homeowner, if possible.
- Checking your home inspection report from when you purchased the house.
- Consulting with the local municipal building office for public records.
When in Doubt: Consulting With a Professional
In some cases, you may struggle to identify the type of pool you have using visual and tactile methods. If the pool is old or significantly resurfaced, the material clues may be obscured. At this point, reaching out to a pool contractor or inspector could be helpful.
Professionals can:
- Conduct surface tests using core-sampling tools to inspect composition layers.
- Use thermal imaging to visualize the structural density and type.
- Provide clarity on what maintenance is required for either pool material.
If planning a major renovation, getting an expert opinion is not just recommended but critical.
Why It Matters: Understanding Your Pool Type Affects Your Maintenance Strategy
Once you’ve identified whether your pool is built from gunite or concrete, you gain important insights that directly impact its care.
Crack Tolerance and Resurfacing Trends
- Gunite pools can tolerate small cracks better due to the application process that results in a slightly more flexible shell.
- Concrete pools are more prone to cracking due to drying shrinkage and soil movement, which makes crack sealing essential in their maintenance.
Long-Term Value and Resale Considerations
If you’re planning to sell your property, it’s valuable information for your listing. Gunite pools often add more resale value because of their custom designs and perceived durability.
However, outdated, improperly maintained concrete versions may require more investment to be appealing to potential buyers.
Refinishing and Renovation Costs
Refinishing a pool is typically needed every 7–10 years, and the type of construction material can affect this process:
| Pool Type | Average Refinishing Frequency | Typical Refinishing Cost | Reasons for Refinishing |
|---|---|---|---|
| Gunite | 10+ years (depending on finish used) | $4,000 – $10,000 | Peeling plaster, surface dullness, staining |
| Concrete | 7–9 years | $3,500 – $9,000 | Cracks, surface spalling, plaster wear |
Comparing Maintenance and Repairs
Because both gunite and concrete pools are essentially forms of concrete, many maintenance steps are similar. However, their structural makeup affects how they handle different types of wear, water pressure, and ground movement.
Crack Repair
Gunite is less likely to develop structural cracks, but small surface cracks are still possible. They are typically sealed with epoxy or polyurethane injected into the joint.
Concrete pools often require more extensive crack repair, especially for deeper or wider fractures that may compromise water integrity.
Replastering
Replastering is a common need for both, and is often triggered by:
- Fading or discoloration
- Spalling (chipping of the surface)
- Rough or uncomfortable texture
The process for applying new plaster is similar in many cases, although preparation techniques can vary depending on the original structure and finish type.
Advantages of Gunite vs. Concrete
Gunite Advantages
- Highly customizable and suited for complex designs
- Quick construction time — ideal for busy schedules
- Smoother integration with rebar for reinforced structures
- Better performance over expansive or mixed-soil conditions
Concrete Advantages
- More uniform finish due to traditional casting methods
- Familiarity for contractors in regions where gunite application is less common
- Often budget-friendly in construction unless extensive redesign is involved
Tips for Longevity in Both Gunite and Concrete Pools
Maintain Stable Water Chemistry
Balanced pH levels and proper chlorine (or salt) content prevents surface etching and prolongs the life of your pool’s finish regardless of the shell type. Maintaining your chemistry at least once a week can prevent long-term damage.
Monitor for Cracks and Leaks
Even a small hairline crack can develop into a major structural issue if not treated early. Regular visual inspections—especially after seasonal temperature changes—can help you catch problems early.
Schedule Professional Inspections
While self-inspections offer peace of mind, having a professional evaluate your pool’s condition every 2–3 years is a smart investment in longevity.
Conclusion: Knowing Your Pool’s Structure Enhances Care and Enjoyment
Understanding whether your swimming pool is made from gunite or poured concrete is more than a technical curiosity—it’s essential for proper care, maintenance, and potential upgrade projects. While both offer strong, durable options for an in-ground backyard oasis, the method of construction greatly affects maintenance costs, crack resilience, design possibilities, and long-term performance.
Whether you’re preparing for resale, planning a renovation, or simply curious about the best way to maintain your backyard retreat, this guide should help you answer the question: How do I know if my pool is gunite or concrete? By combining a visual assessment with historical records and—if needed—professional insight, you can confidently move forward in preserving and enhancing your investment.
Remember that both gunite and concrete pools serve as excellent backyard features; the key is knowing how to care for the specific structure beneath the water to ensure it lasts for decades to come.
What is the difference between gunite and concrete pools?
Gunite and concrete pools are often confused because both are types of shotcrete pools. The primary difference lies in the mixing process. Gunite is a dry-mix cement that is mixed with water at the nozzle during application, while concrete, or “wet-mix,” is pre-mixed with water before being sprayed. This distinction impacts the application process and finish, but once fully cured, both materials become structurally similar.
While both types offer durability and flexibility in design, gunite allows for more precise shaping because it hardens more quickly. Concrete pools, on the other hand, may take longer to cure and can be more prone to cracking if not applied correctly. Knowing whether your pool is gunite or concrete can help in understanding maintenance and repair needs, though for most homeowners, the differentiation is mostly relevant during construction or major renovations.
How can I visually identify if my pool is made of gunite or concrete?
Visually inspecting your pool may not provide a definitive answer, as gunite and concrete look quite similar once cured. However, you can look for fine details like surface texture and finish. Gunite pools often have a smoother finish, because the material can be more precisely applied. In contrast, concrete pools sometimes have a rougher or more irregular surface due to the wet-mix application process and the way it settles.
Another visual clue comes from the pool’s construction documentation or from markings left behind during the building process. Sometimes, contractors will label the type of material used. Also, inspect the area around plumbing and coping—it may reveal underlying material texture. While visual cues can help, a professional opinion or construction records are often needed for certainty.
Are there specific maintenance differences between gunite and concrete pools?
Once constructed, there are minimal maintenance differences between gunite and concrete pools because both are made from similar compounds. Both types require regular cleaning, chemical balancing, and occasional resurfacing. However, gunite pools typically offer a smoother surface that may resist algae buildup more effectively, potentially reducing the frequency of scrubbing and chemical treatments needed for algae control.
Another factor to consider is cracking. Both pool types can develop cracks, but due to differences in application, gunite might be less prone to early cracking. If cracks do occur, repair methods are similar—often involving patching with a cementitious compound. Ultimately, the type of plaster, tile, and coping installed on the pool deck may have a larger impact on maintenance than the underlying shotcrete material.
Can I determine my pool type by touching the surface?
Touching the surface of your pool can offer clues about the type of material used. Gunite, especially when properly troweled and coated, typically feels smoother than concrete. This is because gunite is sprayed with less water, allowing for tighter compaction. When rubbed, the interior surface of a gunite pool may resemble a finely textured wall, depending on the finish coat.
Concrete pools, in contrast, may feel slightly rougher or more uneven, especially if air pockets or inconsistencies developed during the wet-mix spraying process. However, many pools are plastered with a smooth finish coat of marcite or pebble, which can obscure the base material’s texture. If you are unsure, it’s best to consult construction records or speak to a qualified pool professional for a definitive identification.
How does the age of my pool relate to whether it’s gunite or concrete?
Pool construction methods have evolved over time, and the age of your pool can give you a general idea of what type of material you might have. Gunite has been around since the early 20th century but gained popularity in the 1960s and 1970s, especially as backyard pool designs became more customized. If your pool was built during or after this era, there’s a good chance it was constructed using either gunite or concrete.
Concrete pools, particularly those built prior to the 1960s, were more common when transportation of pre-mixed concrete was limited or when projects demanded a slower curing process. However, since both materials were sometimes used interchangeably by local contractors, age alone is not a guarantee. To confirm, it’s valuable to seek documentation or evidence such as old construction photos or contractor records.
Do I need a professional to identify if my pool is gunite or concrete?
Identifying whether your pool is made of gunite or concrete might require the help of a professional, especially if there are no records or visible indicators. A pool contractor who specializes in resurfacing, renovation, or repair will often be able to determine the material based on construction techniques and surface characteristics. In some cases, a core sample can be taken and analyzed, though this is a more invasive method.
Professionals bring expertise and tools that help assess not only the type of material but also the structural integrity of the shell. This can be useful for planning any future repairs or upgrades. If you’re considering significant renovation or a chemical system upgrade, knowing the construction type can guide better decision-making. However, for general pool ownership and maintenance purposes, knowing the material may not always be necessary.
Why does it matter whether my pool is gunite or concrete?
Understanding whether your pool is gunite or concrete can be important for major renovations, resurfacing, or structural repairs. Gunite’s dry-mix approach allows for more precise sculpting, which can affect the complexity and cost of modifications. Also, certain pool features like beach entries, vanishing edges, and built-in spas are often constructed using gunite due to its adaptability.
From a longevity standpoint, both materials are durable and long-lasting when properly constructed and maintained. However, knowing your pool type can influence decisions about repair techniques and materials. While most pool owners may not need to know the difference in day-to-day operations, having this information can prove beneficial when working with contractors or assessing structural health concerns.