Does Gunite Pool Crack? – Gunite Pool Fixes and Repairs

Crafted with a mixture of cement, sand, and water, gunite pools are renowned for their durability, flexibility in design, and the ability to fit into any shape or size desired. Yet, like any other structure, they are not without their concerns.

A common question that often looms large for potential owners and those already basking in the luxury of a gunite pool is: Do they crack?

As we dive into the depths of this topic, we’ll explore the reasons behind potential cracks, their implications, and how they can be addressed. So, whether you’re contemplating investing in a gunite pool or seeking to understand more about your current one, this comprehensive guide promises clarity and insight.

Key Takeaways

• Gunite pools can develop cracks over time, but small shrinkage cracks are common and usually not a cause for concern.
  
  
• The causes of gunite pool cracks include improper installation, subpar ground preparation, inadequate reinforcement, incorrect gunite mixture, ground movement and settling, fluctuations in temperature, chemical imbalances, water pressure and pool draining, aging and wear, external impacts, and root invasion.
  
  
• There are two types of cracks in gunite pools: surface cracks and structural cracks. Surface cracks are shallow and typically occur during the curing process, while structural cracks are larger and indicate issues within the pool’s foundation or supporting structure.
  
  
• Surface cracks are mostly cosmetic and can be easily repaired with simple patching. Structural cracks require more extensive repairs to prevent further damage and potential leaks.
  
  
• Visual signs of gunite pool cracks include surface cracks on the plaster or concrete surface and wider, deeper cracks that extend beyond the plaster layer. Water leakage is also a key indication of cracks in a gunite pool.

Does Gunite Pool Crack

Although they are generally durable installations that can last for decades, gunite pools can develop cracks over time. Small shrinkage cracks are common in gunite pools and are usually not a cause for concern. However, if the cracks grow large enough to insert a dime, it may indicate a more serious issue and the integrity of the pool shell might be compromised.

Understanding the causes and types of cracks in gunite pools is important for proper maintenance and repair. Prompt action can help prevent further damage and ensure the longevity of the pool. Regular inspections and addressing any signs of cracking or damage can help homeowners enjoy their gunite pool for years to come.

What Causes a Gunite Pool to Crack

Cracking in gunite pools, while not an everyday occurrence, can indeed be concerning for pool owners. Gunite, a mixture of cement, sand, and water, is lauded for its sturdiness. However, even this robust material has its vulnerabilities. Let’s delve deeper into the intricate causes behind gunite pool cracks:

Improper Installation

• Subpar Ground Preparation: Every pool’s integrity begins with its foundation. Just as a house needs solid ground to prevent structural issues, so does a pool. If the soil beneath the pool isn’t compacted or prepared thoroughly, the pool may settle unevenly. This uneven settling puts stress on certain areas of the pool more than others, leading to potential cracks.
  
  
• Inadequate Reinforcement: The framework of steel reinforcing bars, or rebar, acts as the skeletal structure for gunite pools. If this rebar is spaced too far apart, or if it’s of substandard quality, the pool loses a significant amount of its structural support, making cracks more likely.
  
  
• Incorrect Gunite Mixture: The precise balance in the gunite mixture is paramount. Too much water, for instance, can weaken the mixture, making it less durable and more prone to cracks.

Ground Movement and Settling

• Soil Expansion and Contraction: Soils, especially clay-rich ones, have a penchant for expanding when they absorb water and contracting when they dry out. This cyclical movement can exert a continuous push and pull on the pool’s structure, leading to potential fractures.
  
  
• Seismic Activity: In regions where earthquakes are common, the ground can shift abruptly. Even minor tremors can lead to stress on a gunite pool, causing cracks or exacerbating existing ones.

Fluctuations in Temperature

• Thermal Stress: Just as roads can crack due to temperature changes, so can gunite pools. When the temperature rises quickly, the gunite expands; when it drops, it contracts. This repetitive cycle can lead to what’s known as “thermal fatigue,” resulting in cracks over time.

Chemical Imbalances

The chemistry of pool water isn’t just about keeping it clear and algae-free. Chemical imbalances, especially those leaning towards high acidity, can slowly erode the gunite’s surface. This weakening of the surface makes the underlying structure vulnerable to cracks.

Pool plaster acts as a protective layer for gunite. When this plaster is compromised due to chemical imbalances, the gunite beneath can become more susceptible to external stressors and eventual cracking.

Water Pressure and Pool Draining

The pressure exerted by the water inside the pool provides a balance against the pressure from the soil outside. If a pool is drained too rapidly, this balance is disrupted, and the sudden change can cause the pool’s structure to crack.

It’s also worth noting that the sun’s heat can exacerbate this. Draining during cooler periods can reduce the risk of thermal stress cracks.

Aging and Wear

Like any structure, a gunite pool is subject to the natural wear and tear of time. Minor surface cracks may appear as the pool ages. While these might seem cosmetic, if left unchecked, they can evolve into deeper, structural cracks.

External Impacts

Accidents happen. Whether it’s a heavy piece of patio furniture being blown into the pool during a storm or a large rock falling into it, these sudden impacts can cause immediate damage or create weak points that may crack later.

Root Invasion

Nature has its way of reclaiming space. Trees or large shrubs planted close to a pool might have roots that grow towards the pool’s moisture. Over time, these roots can exert significant pressure on the pool walls, leading to cracks.

Types of Cracks in Gunite Pools and Their Implications

Gunite pools are made of concrete and can develop cracks over time. There are two common types of cracks in gunite pools: surface cracks and structural cracks.

Surface Cracks

Surface cracks, also known as shrinkage cracks, are shallower in nature and typically occur during the curing process of the pool. These cracks are commonly found on the surface of the pool or in the tilework. Unlike structural cracks, surface cracks are not a cause for significant concern when it comes to the pool’s overall structural integrity.

Surface cracks are superficial in nature and are usually not associated with leaks or other serious problems. They are a natural result of the curing process and the settling of the pool material. Fortunately, surface cracks are easily repairable using simple patching methods. These cracks are a cosmetic issue rather than a structural one.

Surface cracks in gunite can be caused by a variety of factors, including:

• Shrinkage: If the plaster mix used to create the pool is not correctly proportioned or is not properly mixed, it may shrink as it dries. This can cause thin, spider web-like lines known as shrinkage cracks.
  
  
• Environmental Factors: Harsh weather conditions, especially extreme temperatures, can cause surface cracks. The pool material can contract as the temperature drops, and expand when the temperature increases, leading to cracking.
  
  
• Poor Workmanship: If the pool construction was rushed or done improperly, cracks can form on the surface. This includes failures with steel installation, incorrect mixing or application of materials, and inadequate soil and site preparation.

Structural Cracks

Structural cracks are typically larger in size compared to surface cracks, and their appearance can vary from straight lines to zigzag patterns. These cracks originate within the pool’s foundation or its supporting structure, indicating issues deeper within the pool’s construction. Unlike surface cracks, structural cracks can lead to more extensive problems such as bulging or sinking of the pool structure.

The most critical aspect of structural cracks is their potential to cause leaks. When a crack is categorized as structural, it implies that the pool is either already leaking or is on the verge of developing leaks in a short span of time. These types of cracks are caused by a range of factors including subpar construction, ground movements, and freeze-thaw cycles.

Here are some of the most common causes of structural cracks in concrete:

• Ground Movement: One of the most common causes of structural cracks is the shifting of the soil beneath the pool. This can be triggered by various factors such as earthquakes, soil erosion, or heavy rainfall.
  
  
• Hydrostatic Pressure: This is pressure that is exerted by a fluid due to gravity. If the water pressure outside the pool is higher than the pressure inside, it can cause the pool to “float” or lift, resulting in cracks.
  
  
• Pool Settling: Over time, the weight of the pool can cause it to settle into the ground. If it settles unevenly, it can cause stress on the shell that results in cracking.
  
  
• Poor Construction: As with surface cracks, structural cracks can also be the result of poor construction techniques or materials. This includes using a weak concrete mix or failing to properly reinforce the structure.
  
  
• Freezing and Thawing: In colder climates, the freeze-thaw cycle can lead to structural cracks. When water freezes, it expands. If it seeps into small cracks in a pool’s surface and freezes, it will expand and make the crack larger.

Structural Cracks Vs Surface Cracks

Distinguishing between surface cracks and structural cracks is crucial for determining the appropriate course of action. Surface cracks can be addressed with straightforward patching, whereas structural cracks demand more extensive repairs to prevent further deterioration of the pool’s condition.

Here are the main differences between the two:

Aspect	Structural Cracks	Surface Cracks
Size	Larger, straight or zigzag patterns	Shallower, typically linear or small
Location	Pool’s foundation or supporting structure	Pool’s surface or tile
Effects	Can cause bulging, sinking, and other damage	Mostly cosmetic, minimal impact on integrity
Leak Potential	Indicates leaks or imminent leakage	No significant risk of leaks
Causes	Poor construction, ground movement, freeze-thaw	Curing process, settling of pool material
Repair Complexity	Requires specialized repairs and inspections	Easily repairable with simple patching
Impact on Integrity	Affects structural integrity and safety	Cosmetic concern, no major structural impact

Identifying and Diagnosing Gunite Pool Cracks

Identifying and diagnosing these cracks early is essential to prevent further damage and ensure timely repairs. Below, we’ll explore the visual signs of gunite pool cracks and the tools and methods used to detect them.

Visual Signs of Gunite Pool Cracks

Surface Cracks: Surface cracks are the most common type of cracks found in gunite pools. They are thin, hairline cracks that usually appear on the pool’s plaster or concrete surface. These cracks are often superficial and do not immediately indicate a structural issue. They are typically caused by minor shifts in the ground or the settling of the pool structure over time. While surface cracks are generally cosmetic, it’s important to monitor them as they can potentially widen and lead to more significant problems if ignored.

Structural Cracks: Unlike surface cracks, structural cracks penetrate deeper into the gunite shell and can pose a risk to the pool’s integrity. These cracks are wider, deeper, and may extend beyond the plaster layer. They can run horizontally, vertically, or diagonally across the pool’s surfaces. Structural cracks are typically caused by factors such as poor construction techniques, ground movement, freeze-thaw cycles, and improper water balance. If left untreated, structural cracks can compromise the pool’s structural stability and lead to leaks and further damage.

Leakage: One of the key signs of cracks in a gunite pool is water leakage. If you notice that the pool’s water level is dropping more rapidly than usual and cannot be attributed to evaporation, there may be cracks allowing water to escape. Leaks can be difficult to pinpoint visually, so it’s important to address them promptly to prevent further damage to the pool and its surrounding area.

Uneven Water Level: Cracks can disrupt the water level in the pool, causing uneven water depth. If you observe significant variations in water level across different areas of the pool, it could indicate the presence of cracks affecting water distribution.

Discoloration: Cracks in a gunite pool can create pockets where dirt, algae, and debris accumulate. Over time, these areas can become discolored, making them stand out against the rest of the pool’s surface. Discoloration along crack lines can be an indicator of underlying cracks that require attention.

Tools and Methods for Detection

Visual Inspection: Regular visual inspections by the pool owner or a professional are essential. Walk around the pool and carefully examine all surfaces, paying attention to any visible cracks, discolorations, or irregularities.

Dye Testing: Dye testing involves adding a colored dye into the water near suspected crack areas. If the dye is drawn into the crack, it confirms the presence of a leak. This method helps identify cracks that may not be immediately visible.

Listening Devices: Professionals use listening devices designed to detect the sound of water escaping from cracks. By carefully listening to the pool’s surfaces, they can identify areas where water is leaking due to cracks.

Pressure Testing: Pressure testing the pool’s plumbing system can reveal drops in pressure that may be caused by leaks. This method helps pinpoint the location of hidden cracks.

Underwater Cameras: Underwater cameras are used to visually inspect hard-to-reach areas underwater. They are particularly useful for identifying cracks that are submerged and not easily visible from the pool’s surface.

Acoustic Sensors: Acoustic sensors can detect the sound of water escaping through cracks. These sensors help professionals locate leaks and cracks that might not be visible to the naked eye.

Infrared Imaging: Infrared cameras can identify temperature variations on the pool’s surface, indicating areas where water is escaping through cracks. This method is particularly effective for identifying hidden leaks.

How to Fix Gunite Pool Cracks

Cracks in gunite pools, while distressing, are not uncommon. They can arise from various factors, from natural ground movements to chemical imbalances. Regardless of their origin, it’s essential to address these cracks promptly to prevent them from worsening and compromising the pool’s integrity.

Fixing cracks involves a methodical approach, from accurately diagnosing the type of crack to selecting the right repair method and materials. Whether it’s a minor surface crack or a deeper structural issue, timely action, combined with the right techniques, can restore your pool to its pristine condition.

In this guide, we’ll walk you through the essentials of repairing gunite pool cracks, ensuring longevity and aesthetics.

Materials Needed

Here’s a list of the materials you might need to fix cracks in gunite pools:

• Tape Measure: To measure the length and width of the crack.
• Photographic Camera: To document the condition of the crack.
• Submersible Pump: To drain the pool efficiently.
• Safety Gloves and Goggles: For personal protection during the process.
• Diamond-Bladed Saw: To cut around and sand down the edges of the crack.
• Flat-Head Screwdriver: To scrape down the surface crack and remove loose material.
• Stiff Brush: To clean away dirt, oils, or algae which could interfere with the bond of the filler.
• Pool Putty: To fill in and smooth out small surface cracks.
• Fiberglass Pool Repair Kit: To repair minor structural cracks.
• Grinder: To roughen the surface of minor structural cracks for a stronger bond.
• Pool Plaster: To fill in and smooth out minor structural cracks.
• High-Pressure Epoxy Sealant: To fill in major structural cracks.
• Sandpaper: To sand down any rough edges of the patched area after drying.
• Pool-Suitable Paint (Optional): To paint over the patch if color difference is noticeable.

Assess the Crack

Take the time to thoroughly examine the structural crack in your gunite pool. Use a measuring tape to measure the length and width of the crack. Consider the severity of the situation. Small and shallow cracks are typically surface cracks that can be easily fixed. However, if the crack is deep and extends beyond the plaster surface, it could be a significant structural issue.

In such cases, you’ll likely need a more comprehensive repair strategy, and consulting with a pool repair expert or contractor might be necessary to ensure a long-lasting solution. Be sure to document the condition of the crack with pictures to track its progression over time, especially if it’s a serious crack.

Drain the Pool

Start by draining your pool, as any repair below the waterline requires a dry surface. Consider renting a submersible pump to remove the water effectively, then store this water appropriately, considering its possible effect on your landscape or drainage system. Safety is crucial during this stage, so ensure all power sources are off to avoid any potential accidents.

Prepare the Crack

With the pool emptied and the crack exposed, the next step involves prepping the area for the repair process. Using a diamond-bladed saw, cut around and sand down the edges of the crack. This helps create a clean and smooth surface that would adhere better to the repair compound. Always wear appropriate safety gear, like goggles and gloves, during this stage to protect against accidental debris.

Repair the Crack

Depending on the size and type of the crack, different repair methods are applied.

• Surface Cracks: If it’s a small surface crack, equip yourself with a dive mask and a flathead screwdriver. Once inside the pool, scrape down the crack with your screwdriver, removing any loose material. Widen the crack slightly with your tool to provide a good depth for your filler material. Use a stiff brush to scrub away any dirt, oils, or algae that could interfere with the bond between the filler and crack surface. Prepare a pool putty by mixing equal parts of it and roll it into a snake-like shape with your hands. Forcefully push this putty into the crack, then smooth it out with the flat part of your hand or toll to ensure it sits flush with the surface.
  
  
• Minor Structural Cracks: If the crack is a minor structural one, use a fiberglass pool repair kit. This kit is designed to fix small surface cracks in the pool’s structure. You’ll want to use a grinder to roughen the surface for a stronger bond with the repair material. Once the surface is prepared, use pool plaster to fill and smooth the crack.
  
  
• Major Structural Cracks: For more severe structural cracks, a high-pressure epoxy sealant is often used. This special sealant is designed to penetrate deep into the crack, ensuring it’s filled thoroughly and not just sealed at the surface. Be sure to follow the manufacturer’s instructions carefully, as the exact procedure and drying times can vary.

Let it Dry

After the patch has been applied, it’s important to let the area dry thoroughly. The drying time may vary according to the manufacturer’s instructions, so be sure to comply to ensure the effectiveness of the repair. Depending on the product used, this may take a few hours or even a couple of days.

Sand the Patched Area

Once your patch has fully dried, sand down any rough areas until you have a smooth surface. This step is essential to ensure that the repaired area integrates well with the rest of the pool surface and does not cause any discomfort for people using the pool.

Paint over the Patch (Optional)

If the repaired area’s color significantly differs from the rest of your pool, you might want to consider painting over it. Make sure to use a type of paint specifically designed for pools. Carefully follow the paint manufacturer’s instructions for the best result.

Preventing Cracks in Gunite Pools: Essential Tips

Preventing cracks in your gunite pool requires a combination of proper construction techniques, regular maintenance, and attentive care. Below, we’ll explore key strategies to help you keep your gunite pool in pristine condition and minimize the risk of cracks.

Quality Construction and Design

The foundation of crack prevention begins with the initial construction and design of your gunite pool. Engage with experienced and reputable pool builders who understand the complexities of gunite application. Ensuring proper thickness and structural reinforcement during construction is crucial. Additionally, consider factors like soil conditions, water table levels, and local climate when designing your pool to minimize potential stress on the pool shell.

Controlled Curing Process

The curing process plays a significant role in preventing cracks. Gunite requires adequate time to cure and strengthen. Avoid rushing this process and ensure the pool is properly moistened and covered during curing to prevent rapid evaporation, which can lead to cracks.

Regular Maintenance

Ongoing maintenance is key to preventing cracks in your gunite pool:

• Balanced Water Chemistry: Maintain proper water chemistry to prevent corrosion of the pool shell. Improper water balance can weaken the concrete over time, making it more susceptible to cracks.
  
  
• Proper Filtration and Circulation: Effective filtration and proper circulation help prevent uneven pressure on the pool shell, reducing the risk of cracks.
  
  
• Controlled Temperature Changes: Sudden temperature changes can cause expansion and contraction, leading to cracks. Gradually warm up or cool down the pool water to minimize stress on the pool shell.

Regular Inspections

Periodic inspections by a professional can identify early signs of cracks or structural issues. Address any concerns promptly to prevent small issues from escalating into larger problems.

Avoid Heavy Impact

Sharp objects or heavy impact can cause stress fractures in the gunite surface. Avoid dropping heavy objects into the pool and instruct swimmers to exercise caution.

Avoid Draining Completely

Completely draining a gunite pool can cause the shell to shift or crack due to the loss of hydrostatic pressure. If necessary, consult a pool professional before draining your pool.

Expansion Joints

Incorporating expansion joints into your pool’s design accommodates the natural expansion and contraction of the concrete due to temperature changes. These joints help prevent cracks by allowing controlled movement.

Proper Landscaping

Landscaping around the pool area can impact the soil and water drainage. Ensure proper grading and drainage to prevent soil erosion and excess water accumulation, both of which can affect the pool’s structural integrity.

How Much Does It Cost to Repair a Gunite Pool Crack

The cost to repair a gunite pool crack can vary depending on the size, severity, and location of the crack, as well as the specific repair method used. On average, homeowners can expect to spend anywhere from $500 to $2,500 for pool crack repairs. However, more extensive or complex repairs can cost several thousand dollars.

Some factors that can affect the cost of gunite pool crack repairs include:

• Crack size: Smaller cracks may be easier and less expensive to repair compared to larger or more severe cracks.
• Number of cracks: If there are multiple cracks in the gunite pool, the cost of repairs will naturally be higher.
• Location of the crack: The location of the crack, such as in the pool shell or in the coping or tile work, can impact the cost of repairs.
• Repair method: The specific repair method used can influence the cost. Injection of epoxy or polyurethane is a common technique for gunite pool crack repair, but other methods like epoxy grout or polymer mortar may also be used.
• Additional repairs: Depending on the extent of the damage, additional repairs such as resurfacing the pool or replacing tiles may be necessary, which can increase the overall cost.

It’s important to note that these cost estimates are just rough averages and can vary based on factors specific to your pool and location. To get an accurate cost assessment, it’s recommended to consult with a professional pool contractor who can assess the damage and provide a detailed estimate.

Dealing with Cracks in Gunite Pools During Winter

Winter can be a challenging time for gunite pools, as freezing temperatures and fluctuating weather conditions can exacerbate existing cracks or lead to the formation of new ones. Preventing and addressing cracks in gunite pools during winter requires careful preparation, maintenance, and timely intervention. In this article, we’ll explore how to manage and mitigate the impact of cracks on your gunite pool during the colder months.

Understanding Winter-Related Cracking

Gunite pools are not immune to cracking during winter. The freeze-thaw cycle is a common culprit behind crack formation. When water enters existing cracks or penetrates the porous surface of gunite, it expands as it freezes, putting pressure on the surrounding material. This expansion can widen cracks or create new ones. Additionally, the contraction that occurs when the ice melts can further stress the pool’s structure.

Preventive Measures

• Winterize Properly: Before winter arrives, properly winterize your pool by following manufacturer guidelines. Lower the water level, balance chemicals, clean the pool thoroughly, and add winterizing chemicals. This minimizes the risk of freeze-related damage. To know more, read our gunite pool winterization article.
  
  
• Maintain Proper Water Level: During winter, keep the water level below the tile line to prevent water from freezing in the expansion joints or existing cracks. Water trapped in these areas can expand when frozen, leading to further cracking.
  
  
• Cover the Pool: Use a well-fitted pool cover to protect the pool’s surface from the elements. A sturdy cover helps minimize water infiltration and shields the pool from freezing temperatures.
  
  
• Avoid Draining Completely: While it might be tempting to drain the pool completely for winter, it’s generally not recommended for gunite pools. A certain amount of water in the pool helps counteract the upward pressure from groundwater, which can reduce the risk of shell movement and cracking.

Dive into these comprehensive guides to gain a thorough understanding of common gunite pool issues, and equip yourself with the knowledge to keep your pool in top condition.

Can Gunite Pools Pop Out of the Ground: Discover the potential causes and preventive measures behind the alarming issue of gunite pool “pop-outs” in this insightful article. Gain valuable insights to safeguard your pool investment.

Can Gunite Pools Sink: Delve into the depths of gunite pool stability with this article, addressing the unsettling question of pool sinking. Uncover the factors and solutions to ensure your pool remains firmly in place.

Conclusion

While gunite pools are renowned for their durability and strength, the potential for cracks to develop cannot be entirely discounted. A range of factors, including soil movement, improper installation, fluctuating temperatures, and inadequate maintenance, can contribute to the formation of cracks over time.

However, with proper construction techniques, regular maintenance, and prompt repair of any minor issues, the risk of significant cracking can be minimized. Homeowners investing in a gunite pool should remain vigilant and proactive in caring for their pool to ensure its longevity and minimize the likelihood of cracks forming.

Frequently Asked Questions