When installing an above ground pool, one of the most important yet often overlooked steps is properly preparing the ground beneath it. The surface you place under your above ground pool significantly impacts the longevity of the structure, the comfort of the swimming experience, and the overall aesthetics of your backyard setup. Whether you’re setting up a small kiddie pool or a full-sized family pool, choosing the best underlayment can prevent damage, deter weeds, improve insulation, and provide a smooth, even surface.
In this article, we’ll explore the different materials you can use to line under your above ground pool, analyze their pros and cons, and help you determine the best choice based on your specific needs, budget, and climate.
Why Proper Underlayment Matters for Above Ground Pools
Proper ground preparation is not just a cosmetic or comfort consideration—it’s essential for the structural integrity of your pool. An uneven or improperly prepared surface can lead to several common issues, including:
- Damage to the pool liner from rocks, roots, or sharp objects
- Uneven water distribution due to an unstable foundation
- Weed and pest intrusion from the soil below
- Accelerated wear and tear from temperature extremes or moisture
Understanding these potential hazards will help you make a more informed decision about what to use under your above ground pool.
Top Materials for Under an Above Ground Pool
There are several materials on the market specifically designed for use under above ground pools. Each has unique advantages and considerations. Let’s take a look at the most common materials used for this purpose.
1. Sand
Sand remains one of the most popular choices for pool underlayment due to its affordability and effectiveness. It provides a smooth, level surface that can conform to slight dips in the ground, offering a protective cushion for the pool liner.
Pros:
- Cost-effective
- Natural leveling properties
- Soft texture protects liner from sharp objects
- Easy to find and install
Cons:
- Requires thorough sifting to remove stones and debris
- May shift over time, especially in moist areas
- Can attract weeds if not properly covered or contained
To get the best results with sand:
- Excavate the ground to create a flat base
- Sift the sand to remove rocks and grit
- Apply a layer 2 to 4 inches thick
- Tamp the sand to ensure it’s evenly compacted
2. Foam Pool Padding
Foam padding—often made of closed-cell polyethylene—is one of the most advanced and effective underlayments for above ground pools. It provides superior protection and insulation.
Pros:
- Offers maximum cushioning and protection for the pool liner
- Acts as an insulator, helping maintain water temperature
- Inhibits cold transfer from the ground, improving swimmer comfort
- Reduces wear from ground surface friction
Cons:
- More expensive than sand or felt
- Needs to be covered or rolled out carefully to avoid creases
- Not suitable for all ground types without preparation
Foam padding typically comes in rolls, is easy to install, and works well in combination with other underlayers like sand or polymeric sand. It’s especially beneficial for people who want a luxurious, comfortable feel to their pool floor.
3. Landscape Fabric or Underlayment Felt
Landscape fabric, also known as geotextile fabric or underlayment felt, is a breathable fabric that allows moisture and air to pass through while blocking weeds and pests.
Pros:
- Excellent for weed prevention
- Durable and long-lasting
- Can be used alone or beneath other underlayments
- Helps create a barrier between the pool and the soil
Cons:
- Does not offer significant cushioning
- May tear easily if not handled carefully
- Risk of weeds growing around the edges if not trimmed properly
Felt is commonly used with sand or foam padding to enhance ground preparation. It can also be cut to shape precisely, making it ideal for irregular pool bases.
4. Concrete or Paver Base
A concrete or paver foundation provides a solid, level base that eliminates ground issues. While more permanent and expensive, this underlayment option is perfect for dedicated pool spaces.
Pros:
- Extremely durable and stable
- Completely level and resistant to shifting
- Minimal maintenance after installation
- Enhances the aesthetic value of the pool area
Cons:
- High upfront cost
- Requires professional installation
- Difficult to remove or repurpose if the pool is relocated
- Requires proper drainage to avoid water pooling underneath
A concrete base should include a crushed gravel sub-base to manage water drainage and prevent cracking. It’s best suited for steel-walled or resin pools that are designed for long-term installation.
5. Vinyl Liner Protection Mats
These mats are specifically designed for use under above ground pools. They’re made of thick, flexible materials that provide a barrier between the liner and the ground surface.
Pros:
- Tailored for pool use
- Offers optimal protection against punctures
- Easy to clean and maintain
- Some are UV-resistant and anti-microbial
Cons:
- Higher cost per square foot
- May not be as cushioned as foam padding
- Typically used in conjunction with other underlayment layers
Liner protection mats can be laid directly over sand or stone surfaces, giving you the benefits of ground protection without sacrificing durability or comfort.
How to Prepare the Ground Before Adding Underlayment
Before you even think about choosing underlayment, it’s critical to prepare the ground beneath your pool correctly. The success of your underlayment depends on the evenness and cleanliness of the underlying surface.
Step 1: Clear the Area
Remove all grass, plants, rocks, stones, sticks, and other debris from the installation area. This ensures a clean and stable foundation.
Step 2: Level the Ground
Use a shovel, rake, or leveling tool to flatten the area where your pool will sit. Uneven ground will lead to an unstable base that could damage the pool structure or liner.
Step 3: Tamp the Soil
Once leveled, tamp down the soil to ensure a firm and stable base. This can help prevent shifting and settling after the pool is filled.
Step 4: Install Drainage Layer (Optional but Recommended)
A layer of crushed gravel or sand can improve drainage and help prevent moisture from affecting your underlayment. Especially important in areas with poor drainage or heavy rainfall.
Step 5: Lay Landscape Fabric
To minimize weed growth and offer additional protection, lay down a layer of landscape fabric before adding your selected underlayment material like sand or foam.
How to Choose the Best Underlayment for Your Pool
Selecting the right underlayment involves evaluating several key factors, from installation type to climate and budget. Let’s explore what to consider when making your decision.
1. Budget Considerations
If you’re working with a limited budget, sand is typically the most affordable choice. Foam padding and concrete foundations are on the higher end of the price spectrum. For long-term investments, however, the upfront cost can be justified by the enhanced durability and reduced risk of pool liner damage.
2. Climate and Weather Factors
In areas with cold winters or extreme sunlight, materials like foam padding or UV-resistant vinyl mats can provide insulation and protection from temperature shifts. Sand alone may be less effective in these conditions, especially if it’s exposed directly to the elements.
3. Pool Type and Usage
Consider whether your pool is seasonal or permanent, and how often you plan to use it:
- Basic temporary pools (like inflatable or small frame pools): sand or felt is usually sufficient
- Seasonal above ground pools: foam padding with sand offers the best balance
- Permanent in-ground installations: concrete or stone bases are ideal
4. Ground Conditions
If your ground contains a lot of rocks or roots, you may need a more forgiving underlayment like sand or foam padding. For soft or muddy ground, a gravel sub-base followed by stable foam padding or concrete is recommended.
5. Personal Preferences
Some pool owners simply prefer a plusher, softer bottom feel. Foam padding and high-quality liner protection mats offer a much more comfortable walking experience, especially for barefoot or young children.
Comparing Underlayment Options: A Quick Overview
A brief summary of underlayment choices can help guide your decision:
| Material | Cost | Protection Level | Durability | Ease of Installation | Best For |
|---|---|---|---|---|---|
| Sand | Low | Moderate | Moderate | Easy | Temporary pools, budget-friendly installations |
| Foam Padding | Medium-High | Excellent | Excellent | Moderate | Comfort-focused or high-end pools |
| Landscape Fabric | Low-Medium | Moderate | High | Easy | Weed control, base layers for extra underlayment |
| Concrete | High | Excellent | Excellent | Difficult | Permanent installations, stability |
| Protection Mats | Medium-High | Excellent | High | Easy | Protecting expensive liners, luxury installations |
Conclusion: Finding the Best Fit for Your Situation
There is no single “one-size-fits-all” solution when it comes to choosing the best material to put under your above ground pool. The ideal underlayment will depend on your budget, usage frequency, local climate, and existing ground conditions.
To recap:
- For a standard seasonal pool with a budget-friendly approach, sand and landscape fabric are reliable and accessible choices.
- For enhanced comfort and protection, especially for permanent setups, foam padding offers unrivaled value.
- If you’re building a permanent or luxury pool, investing in a concrete or stone base with protective mats ensures long-term quality and usability.
By taking the time to properly prepare your pool’s foundation and select the best underlayment, you’ll enjoy a safer, more comfortable, and long-lasting swimming experience.
Final Takeaway
Don’t underestimate the importance of what lies beneath your pool. A little effort and investment in proper underlayment can go a long way in extending the life of your pool, protecting your investment, and maximizing enjoyment. Whether you go with sand for its simplicity or foam padding for its premium protection, always ensure your choices match your needs, your environment, and the type of pool you own.
So next time you’re preparing for a backyard splash, remember—the right base can make all the difference.
What materials are best suited for placing under an above ground pool?
The best materials to use under an above ground pool include sand, concrete, solid foam padding, and specialized pool underlayment. Sand is a popular and cost-effective option because it provides a smooth, even surface that can cushion the pool’s liner and accommodate slight imperfections in the ground. Solid foam padding or foam underlayment is another great choice, particularly for uneven surfaces, because it provides a protective layer against sharp objects and offers insulation.
Concrete is an option for those looking for a permanent, long-term installation. It provides a level and durable surface but may require additional cushioning for the pool liner. It’s important to avoid rough or uneven materials like gravel or dirt with exposed rocks, as these can damage the liner over time. The main goal is to achieve a smooth, level base that supports the pool structure and protects the liner from damage.
Why is preparing the ground important for an above ground pool?
Proper ground preparation is essential for the stability, longevity, and safety of an above ground pool. An uneven or inadequately prepared surface can cause the pool walls to shift or lean, leading to structural damage over time. Additionally, sharp objects or rough surfaces beneath the pool can puncture or wear down the liner, resulting in leaks and expensive repairs. A well-prepared base ensures even weight distribution and helps maintain the integrity of the pool.
The ground should be cleared of grass, rocks, roots, and debris before leveling it with a suitable material like sand or foam padding. Compacting the ground and ensuring proper drainage are also important steps. This preparation not only protects the pool but also enhances comfort underfoot and prevents settling issues. Although it may seem like an extra step, properly preparing the ground significantly contributes to the pool’s durability and ease of maintenance.
Can you use pavers as a base for an above ground pool?
Yes, pavers can be used as a base for an above ground pool, and they offer a durable and aesthetically pleasing foundation. Pavers provide a level, stable surface that supports the walls and helps prevent shifting or tilting of the pool structure. They can also be arranged in various patterns to enhance the appearance of your backyard while offering excellent drainage when installed with appropriate spacing and a gravel base underneath.
However, it’s important to install a soft underlayment such as sand or foam padding on top of the pavers to protect the pool liner from abrasions. Using pavers without cushioning can lead to premature wear and punctures. Additionally, paver installation can be labor-intensive and more expensive than simpler ground preparation methods like using sand alone. Despite the effort, pavers can be a worthwhile investment for those who want a long-term, stable base with a polished look.
Is sand necessary under an above ground pool?
Sand is widely recommended under an above ground pool because it creates a smooth, protective layer that helps prevent punctures in the liner and accommodates minor ground irregularities. It’s also relatively inexpensive and easy to work with. Sand helps cushion the weight of the pool and water while providing a more comfortable surface for walking and lounging. For many pool owners, sand is a preferred option due to its availability and simplicity.
However, sand is not always necessary, depending on the installation site and the overall condition of the ground. In some cases, specialized foam padding or underlayment provides sufficient protection and comfort without the need for sand. On perfectly flat concrete pads, an above ground pool doesn’t require sand, but a cushioned underlayment should still be used. Ultimately, the decision to use sand depends on your pool location and how protective you need the base layer to be for long-term performance.
What are the benefits of using foam padding beneath an above ground pool?
Foam padding, also known as pool underlayment, offers several benefits for above ground pool bases. It cushions the pool liner against abrasions and punctures from small rocks or uneven ground. This padding provides a more uniform surface and enhances comfort for swimmers walking inside the pool. It also acts as an insulating layer, helping protect the liner from temperature fluctuations and ground moisture.
Foam padding is lightweight and easy to install, making it a popular choice for pool owners who want a reliable and straightforward base. It works particularly well when placed on top of a hard surface like concrete or pavers, where it can soften the impact on the liner. Some foam products are designed specifically for pools and may include moisture-resistant properties. While slightly more expensive than sand, foam padding delivers excellent protection and contributes to a longer lifespan for your pool.
Can you install an above ground pool directly on grass?
No, it’s not recommended to install an above ground pool directly on grass. Grass and soil can become uneven over time due to compaction, moisture absorption, or plant growth, which may lead to an unlevel pool. Roots, rocks, and insects beneath the grass can also pose risks to the pool’s liner, potentially causing punctures or accelerated wear. Additionally, grass can retain moisture and create a breeding ground for mold or unpleasant odors under the pool.
If you decide to place your pool on grass, you should remove the grass and topsoil first to provide a more stable, level surface. It’s also essential to lay a protective underlayment, such as sand or foam padding, to prevent damage to the liner. Taking these steps helps reduce the risk of an uneven base while improving the longevity and safety of your above ground pool installation. A prepared base is always the better choice in terms of performance and protection.
What should I avoid putting under my above ground pool?
You should avoid using rough, uneven, or sharp materials like gravel, stones, or unprepared dirt under an above ground pool. These substances can create pressure points or abrasions that damage the pool liner over time. Additionally, materials with inconsistent textures may lead to discomfort for swimmers and uneven settling, which can cause structural issues in the pool walls or seams.
Avoid using organic materials such as leaves, bark, or compost as they can rot, leading to an uneven base and potential liner damage. Pressure-treated wood or scrap lumber may also contain chemicals or splinters that could harm the liner. Always prioritize smooth, level, and protective materials, and ensure that the base is free of any debris before installation. Proper base material selection is key to ensuring both safety and pool longevity.