Swimming pools are a luxury addition to many homes, but they require consistent maintenance to remain safe and functional. Over time, structural wear, ground movement, and poor construction can lead to cracks. Not all cracks are created equal — some are surface-level imperfections, while others may indicate serious structural damage.
Identifying whether a pool crack is structural is crucial to preventing more expensive repairs or even complete pool failure. In this detailed guide, we’ll walk you through the key signs, evaluation methods, and next steps to determine if your pool crack is affecting its fundamental structure.
Understanding the Different Types of Pool Cracks
Before diving into how to determine if a pool crack is structural, it’s important to understand the types of cracks you may encounter. Pool cracks generally fall into two main categories:
Surface or Hairline Cracks
These are the most common types of pool cracks. They are usually:
- Thin and shallow
- Found in the plaster or tile finish
- Caused by normal wear and temperature changes
- Not indicative of deeper pool structure issues
Hairline cracks often don’t affect the integrity of your pool’s structure and can usually be sealed or resurfaced.
Structural Cracks
On the other hand, structural cracks are:
- Noticeably wide or deep
- Found running through the concrete shell, tile line, or corners
- Usually a result of foundation movement, soil settling, or poor construction
- Potentially leading to serious leaks and damage
These types of cracks warrant immediate attention and are the focus of this article.
Signs That Your Pool Crack May Be Structural
Detecting structural cracks isn’t always straightforward, but several visual and environmental indicators can point to serious issues:
Crack Width and Depth
To evaluate pool cracks, start with a simple visual inspection:
| Crack Classification | Width and Depth | Typical Cause | Is It Structural? |
|---|---|---|---|
| Hairline | Less than 1/16 inch | Normal expansion/contraction of materials | No |
| Moderate | Between 1/16 and 1/8 inch | Slight settling or ground shifting | Potentially |
| Severe | 1/8 inch or wider | Soil displacement, poor structure, or foundation damage | Yes |
Take note of any crack wider than 1/8 inch, especially if it spans more than a few inches in length.
Crack Location
Where the crack is located in your pool is another significant factor. Structural cracks are often found:
- Along the main walls
- At corners where stress is concentrated
- Along the deep end or steps
- In the pool shell itself beneath the plaster
If a crack appears along the coping (the pool edge), it may signal shifting that affects the entire structure, rather than just cosmetic damage.
Water Loss or Leak Signs
A consistent drop in pool water level can indicate a crack causing leakage. To test:
- Mark the current water level using a waterproof marker on the tile.
- Turn off the pool pump and leave the pool untouched for 24-48 hours.
- Compare indoor water evaporation by placing a bucket filled with pool water next to the pool and marking that too.
If your pool water drops faster than the bucket does, you may have a leak due to a crack.
Multiple Cracks or Spalling
When you notice multiple cracks across different areas of the pool or spalling (where concrete breaks off and exposes the rebar underneath), this signals major structural stress or compromise.
Out-of-Sync Coping or Tile
Tiles or coping that appear uneven, misaligned, or offset could reflect movement beneath the surface. This is one of the strongest indicators of a structural crack because the pool deck or structure has shifted.
Steps to Confirm Structural Damage
Once you’ve identified the visual signs of a crack, confirm whether it affects your pool structure by following this process:
Consult a Pool Professional
While self-inspection can provide clues, the only reliable method for confirmation is hiring an expert. A qualified pool contractor or structural engineer will:
- Analyze ground movement history
- Use pressure testing methods to assess leaks
- Measure crack depth and width
- Check the concrete shell for integrity
They’ll often also employ tools like crack monitors — devices that show ongoing crack activity — to determine whether the damage is still progressing.
Excavation Test for the Wall
If the suspected structural crack lies near the pool wall underground, the contractor might excavate a few inches of backfill around the affected area. If the crack continues below ground, it likely indicates a serious foundation issue.
Assessing Plumbing and Pipe Alignment
If a crack is the result of structural shifting, nearby plumbing or piping systems connected to the pool might show signs of alignment issues or pressure damage.
Leak Testing and Dye Test
While pressure tests show pressure loss in the system, a dye test involves introducing a concentrated liquid dye near suspected cracks. If the dye is pulled into the crack, it confirms a leak. This is especially useful for assessing cracks along the floor or waterline.
Common Causes of Structural Cracks in Pools
Understanding why structural cracks appear helps in determining whether your specific crack is just a symptom or a larger ongoing problem. Here are the primary causes:
Soil Movement or Settling
One of the biggest contributors to structural failure in pools is the ground beneath them. Expansive soils — such as clay — can swell and contract with moisture changes, creating stress on the pool foundation. Other issues include:
- Poor soil compaction during construction
- Water intrusion around the pool shell
- Tree roots shifting soil underneath
Poor Construction or Reinforcement
Lack of proper rebar installation, insufficient concrete strength, or improper waterproofing can all lead to cracks soon after pool construction.
Hydrostatic Pressure Buildup
When groundwater rises and exerts pressure against the bottom of an empty pool, it can cause cracks in the bottom slab or walls. This is especially common during heavy rains or when pool draining occurs in high-water-table areas.
Earthquake Activity or Seismic Shifting
In certain regions, seismic activity can result in ground shifts that affect pool integrity. While not common everywhere, it’s notable in areas like California, Nevada, and Utah.
Lack of Control or Expansion Joints
Properly installed expansion joints between your deck and pool allow for movement without stress buildup. Pools without these features are more prone to stress cracking.
What to Do if Your Pool Crack Is Structural
Once structural damage has been confirmed, timing becomes crucial. Delayed action can lead to worse outcomes and costlier repairs.
Step 1: Stop Using the Pool Immediately
A structural crack means the pool’s shell may no longer be water-tight or strong enough to contain the pressure of the water. Continued use can worsen the crack or cause collapse.
Step 2: Document the Damage
Take clear photos or videos of the affected areas both underwater and above the waterline. Include multiple angles and distances. Detailed documentation helps with insurance claims and contractor assessments.
Step 3: Contact a Structural Pool Contractor
Make sure the contractor is experienced with structural repairs. They should have:
- Access to diagnostic tools like crack monitors and dye tests
- Reinforcement expertise such as installing steel rebar
- Knowledge of local soil conditions
Step 4: Explore Repair Solutions
Depending on the severity of the crack and its cause, possible solutions include:
| Repair Method | Suitable For | Cost Relative to Pool Replacement |
|---|---|---|
| Steel Rebar Reinforcement and Shotcrete | Cracks due to minor structural shifts | 30–60% of new pool |
| Carbon Fiber Straps | Wall or corner cracks from outward pressure | 15–30% of new pool |
| Hydraulic Cement Patching | Minor structural leaks that don’t compromise pool stability | Low |
| Draining and Replastering | Leaks along surface combined with structural repair | 20–40% of new pool |
In cases where the shell integrity is severely compromised or the pool is aged, demolition and rebuilding may be the most cost-effective solution in the long run.
Step 5: Address Ground Movement Issues
If soil shifting caused the crack, simply repairing the crack won’t prevent a future recurrence. Solutions include:
- Installing French drains for water diversion
- Compacting loose soil or using chemical injections
- Stabilizing nearby trees through root barriers
Preventing Future Structural Cracks
After dealing with a structural issue or during ongoing maintenance, implement strategies to prolong your pool’s life and minimize future damage.
Regular Inspections and Maintenance
Perform visual inspections every few months, especially after seasonal temperature changes, heavy rains, or nearby construction projects. Watch for signs of wall bowing, water loss, and spalling.
Proper Drainage Design
Ensure proper landscaping slope and drainage channels guide water away from the pool area. Standing water near the pool shell can destabilize the ground beneath.
Avoid Draining the Pool Unnecessarily
Keep your pool full, especially if you live in a high groundwater area. Refrain from emptying the pool without professional guidance, as hydrostatic pressure can cause damage.
Monitor Nearby Trees and Construction
Tree roots can absorb moisture and cause ground shifting, while nearby construction can result in vibration and soil displacement. Have such activities evaluated for potential pool risks.
Hire a Qualified Pool Construction Company
When building a new pool or repairing an old one, always work with licensed, experienced, and insured professionals. Check for certifications such as those from the National Pool Industry Education Society (NPIES) or local pool associations.
Conclusion: Act on Suspicious Pool Cracks Quickly
Understanding whether your pool crack is structural doesn’t just affect your repair decision — it might affect the value of your home and your safety. A crack may start innocently but can lead to major failures if not managed correctly. Use this guide to stay informed, assess visible signs carefully, and work with experts when needed. By catching these issues early, you’ll protect your investment and ensure years of enjoyment from your swimming pool.
What defines a structural crack in a pool?
A structural crack in a pool is a fissure or break in the concrete or gunite shell of the pool that affects the integrity of the structure. These cracks typically extend through the entire thickness of the pool wall or floor and can indicate underlying problems such as shifting soil, poor construction, or water damage. Structural cracks often appear in patterns, such as stair-step cracks in tiled pools, or in areas where the pool structure is under stress, like near deep ends or walls adjacent to spas.
Unlike cosmetic cracks, which are surface-level and typically limited to the plaster finish, structural cracks are often wider than 1/8 inch and may continue to grow over time. They can be accompanied by signs like sunken pool decking, uneven water levels, or water leakage that is difficult to trace. Identifying a crack as structural generally requires professional evaluation, especially to determine whether it’s caused by foundational movement or pressure from outside forces.
Can small cracks in my pool be structural?
While small cracks might seem harmless, some can indeed be structural depending on their location and movement. Hairline cracks in the plaster are usually cosmetic and do not penetrate the underlying concrete structure. However, if a seemingly small crack is located near a major structural component like a beam or wall, or if it appears in a pattern that suggests movement, it may indicate a larger issue that deserves further investigation.
It is essential to observe small cracks for signs of progression, like widening, lengthening, or spalling—where chunks of plaster or concrete break away. These symptoms may indicate that the crack is not just superficial. A professional inspection using tools like a crack monitor or moisture meter can help determine whether the crack is structural and what underlying problems may be causing it.
How do I visually inspect my pool for structural cracks?
Start your inspection at the pool’s waterline and work your way down, both inside and outside the shell. Structural cracks typically appear as jagged or stepped breaks rather than straight lines. Look for irregularities in the pool’s walls and floor, including cracks that run diagonally or form a “Y” shape. Pay close attention to areas where different structures meet, like spas, retaining walls, or stairs, as these are stress points where structural cracks are more likely to appear.
Also, check the surrounding deck and fence. Cracks in the decking that align with cracks in the pool shell, or sunken or uneven concrete, are red flags for structural movement. Additionally, check for signs of water loss unrelated to evaporation or equipment problems. If your pool loses a significant amount of water and you can’t identify the source, a structural crack may be allowing water to escape into the ground beneath the pool.
Can shifting soil cause structural pool cracks?
Yes, shifting soil beneath or around the pool can absolutely lead to structural cracks. If the soil supporting the pool settles unevenly or becomes excessively dry or saturated, it may shift and put pressure on the pool’s structure. This kind of soil movement is often caused by factors such as heavy rains, tree roots drawing moisture, or the natural settling of the ground after construction.
When soil issues are responsible for structural damage, other signs may be present, such as cracks in nearby walls, uneven floors inside the house, or gaps between the deck and the pool coping. In many cases, soil-related damage can worsen over time, especially if the underlying issue isn’t corrected. An experienced pool contractor or foundation specialist can analyze the damage and suggest stabilization or repair measures, like soil re-compaction or drainage solutions.
Should I use a professional to check if my pool crack is structural?
DIY inspection can provide preliminary insight, but to accurately assess whether a crack is structural, it’s best to consult a qualified pool professional or structural engineer. These experts can use specialized techniques, such as crack mapping, moisture testing, and pool leak detection, to determine whether the integrity of the structure is compromised. They can also evaluate factors such as the pool’s construction type, surrounding soil behavior, and the pool’s history (e.g., previous repairs, water loss incidents).
Professionals will not only diagnose the current problem but also recommend the most appropriate method of repair. Structural crack repairs often require techniques like epoxy injection, steel reinforcement, or even partial reconstruction, depending on the severity. Their expert opinion will help avoid unnecessary repairs and ensure that any fixes address the root cause of the crack rather than just its symptoms.
What are the repair options for a structural pool crack?
Repairing structural cracks in a pool typically requires more extensive methods than cosmetic fixes. Common options include routing and sealing the crack with epoxy or polyurethane injections, which fill and stabilize the break from the inside. In more severe cases, installing reinforcing steel or rebar along the crack and applying shotcrete (sprayable concrete) may be necessary to restore structural integrity and prevent further movement.
The effectiveness of a repair method often depends on addressing the underlying cause, such as soil movement or poor drainage, before proceeding with the repair. This might include improving the grading around the pool or adding drainage pipes. A contractor might also suggest partial or full resurfacing after structural repairs to ensure water tightness and aesthetics. The best repair solution should be determined through professional evaluation to ensure a long-lasting fix.
Can I patch a structural crack myself?
While temporary patches for small leaks can be performed using epoxy-based crack repair kits available from pool supply stores, these DIY fixes should not be considered permanent solutions for structural cracks. These kits might help slow or stop water loss in minor cases but do not address the underlying structural issues that caused the crack. Attempting to patch a significant structural crack on your own may lead to recurring problems, extensive water loss, or even pool failure.
For long-term effectiveness and safety, structural cracks should always be evaluated and repaired by a qualified pool professional or a structural engineer. They have the tools, knowledge, and experience to properly diagnose, repair, and reinforce your pool to prevent further damage. Even if you apply a temporary patch, it’s crucial to schedule a professional inspection as soon as possible to avoid escalating structural concerns and costly repairs down the line.