Why Sand Is Used Under Above Ground Pools

If you're planning an above ground pool installation, one of the first questions you'll encounter is: do I really need a sand base? The short answer is yes — and here's why.

Sand serves as a soft, forgiving foundation between the hard ground and your pool's vinyl liner. Without it, even small rocks, roots, or uneven soil can press up through the liner over time, causing punctures, premature wear, and costly repairs. A properly installed 2–3 inch layer of mason sand (also called torpedo sand or washed sand) cushions the liner and distributes the enormous weight of a full pool evenly across the ground beneath it.

Beyond protection, sand is easy to work with. It can be shaped and leveled by hand, allows for fine-tuning, and compacts well enough to stay in place once the pool is filled. Unlike concrete, it's forgiving — if you need to make a small adjustment, you can.

One important note: the sand used under your pool is not the same as filter sand used inside your pump system. Pool base sand should be fine-grained mason sand, free of debris, clay, or sharp particles.

Preparing the Ground for Pool Installation

Before a single shovelful of sand goes down, the ground itself needs to be properly prepared. This step is often underestimated by first-time pool owners, but it's arguably the most critical part of above ground pool base preparation.

Start by clearing the installation area of all grass, weeds, roots, and debris. You'll want to remove the sod and top layer of soil to get down to a firm, stable subgrade. Any soft or spongy spots should be compacted or filled with crushed stone before you proceed.

Leveling is non-negotiable. The entire footprint of your pool — not just the center — must be within 1–2 inches of perfectly level. An out-of-level pool puts uneven stress on the walls, bottom rail, and liner, which can lead to structural failure. Use a long carpenter's level or laser level to check the area from multiple directions before laying your sand.

Once the ground is cleared, level, and compacted, you can lay your sand base. Spread the sand evenly, rake it smooth, and use a long board or screed to flatten it out. Some installers use a homemade screed tool — a long 2x4 dragged across a pair of stakes set at the correct height — to achieve a consistent, even surface.

How Much Sand Is Needed For Different Pool Sizes

The amount of sand required depends on the size of your pool and whether you're using a foam cove or a sand cove around the base of the pool wall (more on that below). Here are estimates for all common round and oval pool sizes:

Keep in mind these are estimates based on a standard 2–3 inch sand bed depth. Depending on how uneven your yard is, you may need additional sand to compensate for low spots. When in doubt, order slightly more than you think you'll need — leftover sand is easy to deal with; running short mid-install is not.

Sand vs. Foam Cove for Above Ground Pools

The cove is the angled transition at the base of your pool wall where the floor meets the side. This area is under constant water pressure and needs to be properly supported to prevent the liner from pulling or tearing at the seam.

You have two options: a sand cove or a foam cove.

With a sand cove, you use the same mason sand from your base to build up a sloped mound around the inside perimeter of the pool wall. The cove is typically 6 inches wide at the base, 4–6 inches high, and sloped at roughly a 45-degree angle. This is a traditional method and works well when done correctly, but it requires skill and patience to shape properly. The cove must be smooth, consistent, and firm — a lumpy or uneven sand cove is one of the most common causes of liner problems.

A foam cove is a pre-formed foam strip that peels and sticks directly to the inside base of the pool wall. It provides a consistent, perfectly shaped cove every time — no sculpting required. Foam coves are typically 3¾ inches high and are installed on top of approximately 3 inches of sand, giving a total cove height of about 7 inches. Because the shape is uniform and the foam is resilient, many professional above ground pool installers prefer foam coves for the reliability they offer.

As you can see in the table above, using a foam cove allows you to use less overall sand because you no longer need to build up the cove from sand alone. For many homeowners, the cost of foam cove is offset by the savings in sand and the reduced labor of having to shape a precise sand cove by hand.

Professional Installation Tips

Experienced above ground pool installers develop a set of best practices over years of working with different yards, soil types, and pool sizes. Here are some of the tips professionals rely on:

• Use mason sand, not play sand or all-purpose sand. Mason sand (also called torpedo sand) is the right grade for pool bases. Play sand is too fine and can shift; coarser sands may have sharp particles that damage liners.
• Wet the sand slightly before final leveling. Lightly moistening the sand helps it compact and stay in place during the smoothing process. It also makes it easier to detect and fill low spots.
• Never install over grass or sod. Grass will die and decompose under the pool, creating voids and uneven settling over time. Always strip the area down to bare dirt.
• Double-check level before placing the bottom rail. Once the pool structure goes up, it's very difficult to correct a level problem without starting over.
• Smooth the sand floor with a floor trowel or float. A perfectly smooth surface means fewer wrinkles in your liner and a more professional finished result.
• Compact gently. Walking on the sand in socks or smooth-soled shoes (not work boots) is a time-honored way to lightly compact the surface without disturbing it.

Common Mistakes When Installing a Pool Base

Even well-intentioned DIY installations can go wrong at the base preparation stage. Here are the most common mistakes to avoid:

• Skipping leveling. This is the number-one cause of pool wall failure and liner stress. Even a 3–4 inch difference from one side to the other puts enormous asymmetrical pressure on the structure.
• Using the wrong type of sand. Sharp construction sand or sandy fill dirt is not the same as mason sand. The wrong material can puncture liners or shift unexpectedly after installation.
• Not accounting for the cove. Some homeowners forget to plan for the cove entirely, leading to a liner that pulls tight at the wall junction and tears prematurely.
• Installing on a slope without proper excavation. If your yard slopes, you need to cut and fill to create a level pad — not simply add more sand on the low side. Sand alone is not a substitute for proper grading.
• Ordering too little sand. Underestimating your needs means scrambling for a second delivery mid-installation. Always add 10–15% to your estimate as a buffer.

Ready to Install Your Pool? Aquarian Pool & Spa Can Help

At Aquarian Pool & Spa, we sell and install above ground swimming pools throughout Southeastern Massachusetts and surrounding towns — including Franklin, Foxborough, Attleboro, Taunton, Mansfield, Norton, Easton, Bridgewater, Plymouth, and the Cape Cod area.

Whether you're purchasing a new pool and want professional installation, or you need help with ground preparation and base work, our team brings years of hands-on experience to every project. We handle the hard parts — so you get to enjoy your pool sooner, with confidence that it's built to last.

Contact us today for:

• Above ground pool sales
• Professional pool installation
• Base preparation and leveling
• Liner replacement and repair

Call us at (401) 332-9183 or use our online contact form to get started. We'd love to help you build the backyard you've been dreaming of.