The liner is the part of an above-ground pool that actually holds the water — the wall, frame, and top rails are just the structure around it. It's also the biggest factor in how the pool looks, since the liner's pattern and color are what you see every time you walk into the backyard. If you haven't settled on a pool yet, start with our above-ground pool buying guide; if the pool's decided and you're down to the liner, this is where that call gets made. Choosing the wrong hang style, or a liner sized wrong for your wall height, is one of the costlier mistakes an owner can make — a liner that doesn't fit usually means draining the pool and starting over. This guide covers the three hang styles, what mil thickness buys you, and how liners get sized.
Liner types: overlap, beaded & unibead
All three styles hold water equally well once installed correctly. The differences are in how they attach, how they look at the waterline, and how easily they're replaced.
| Type | How it attaches | Look & fit | Install ease | Notes |
|---|---|---|---|---|
| Overlap | Drapes over the wall and down the outside a few inches, held by a plastic coping strip over the wall and liner edge | Folded edge and strip visible above the waterline | Easiest for a first-time installer | Most economical; strips allow some depth adjustment |
| Beaded | A formed bead on the liner's top edge snaps into a bead receiver track around the wall | Sits flush against the wall, no visible strip | Moderate — needs a bead receiver track already installed | Easiest to remove and swap later; ordered to an exact fit |
| Unibead (J-hook) | Hangs over the wall on a J-hook edge like an overlap liner, or peels back to expose a bead for a beaded fit | Can present as either style depending on install | Easy, and adaptable to whatever track the pool has | Most versatile; fits pools set up for overlap or beaded hardware |
Overlap liners
An overlap liner is exactly what it sounds like: the top edge drapes over the pool wall and down the outside a few inches, where a plastic coping strip clips over both the wall and the liner to hold it in place. It's the original above-ground liner style and remains the most economical way to line a new pool or replace an old one. Because the strip grips the liner rather than locking it to one fixed point, there's some flexibility in where it sits, giving an installer room to adjust depth or take up minor slack. The tradeoff is cosmetic — the folded edge and strip sit visibly above the waterline, so the finished look is less polished than a beaded liner. For budget-conscious buyers, or anyone relining a pool set up for overlap hardware, it's a dependable, proven choice.
Beaded liners
A beaded liner has a formed bead along its top edge that snaps into a bead receiver track mounted around the inside of the wall. Once snapped in, it sits flush against the wall with no fold-over and no visible strip, giving the pool a cleaner look at the waterline. Beaded liners are also the easiest style to replace later — there's no strip to pry off, so you unsnap the old liner and press the new one into the same track. Because the bead is formed to a specific size, a beaded liner has to be ordered to match the pool's dimensions precisely; it doesn't have the forgiving fit an overlap liner has. This style requires a wall already set up with a bead receiver track, so confirm what your pool's top rail supports before ordering.
Unibead (J-hook) liners
A unibead liner is built with a J-hook edge that lets it hang over the wall the same way an overlap liner does. The difference is underneath: peel away a thin strip along that edge and it exposes a bead, letting the same liner convert to a beaded-style fit. That dual-purpose design makes unibead the most flexible liner style available — it works whether a pool's top rail is set up for overlap coping strips or a bead receiver track, so you don't have to know your exact hardware before ordering — a useful edge when you're relining a pool and aren't sure which hang style the original installer used.
Liner thickness: mil vs. gauge
Liner thickness is measured in mil, or thousandths of an inch, and the common options are 15, 20, and 25 mil. A thicker liner resists punctures, abrasion, and UV breakdown better than a thinner one, and tends to feel more solid underfoot, with less wrinkling over time. A 15 mil liner is the lightest-duty, typically most affordable option; 20 mil is a solid middle ground for most households; and 25 mil is the heaviest-duty choice for owners who want maximum durability and are willing to pay more for it.
You'll also see liners marketed by "gauge" rather than mil. Gauge ratings aren't standardized across manufacturers and are often more of a marketing number than a strict measurement, while mil is a direct, verifiable measurement of material thickness. When comparing liners side by side, use the mil rating as your apples-to-apples comparison point rather than a gauge claim.
How to measure and size your liner
Liners are sized to the pool's shape, footprint, and wall height — all three matter, and getting any one wrong is the most common reason a new liner doesn't fit. For a round pool, you need the wall diameter (12', 15', 18', and so on) plus the wall height — typically 52-inch or 54-inch, the two heights Bay Burst pools come in. For an oval pool, you need the length and width together, such as 20' x 12' or 30' x 15', plus the wall height. A liner ordered for the wrong wall height will leave slack folded over the top, or fall short of the coping strip or bead track, so confirm the actual wall height rather than assume.
Just as important is matching the hang style to what your pool's top rail or coping system supports. An overlap liner needs coping strips; a beaded liner needs a bead receiver track already installed; a unibead liner works with either, which is why it's the safer pick when you're not fully certain what hardware your pool uses. If you're deepening or otherwise modifying an existing pool, look for an expandable liner made with extra material for a taller wall. When in doubt, measure twice — a liner is too costly to reorder over a close-but-not-exact measurement.
Patterns, warranty & lifespan
Liners come in a range of patterns and colors, from solid blues to stone- and tile-look prints, so there's room to match the liner to your yard's style. Pattern is purely cosmetic and has no bearing on how the liner attaches or how long it holds up. Liner warranties vary by manufacturer and mil thickness, so check the coverage on whichever liner you choose; lifespan comes down to installation quality and ongoing care.
A typical above-ground pool liner lasts roughly 8 to 15 years with good care, though where you land in that range depends on factors you control. A floor pad installed underneath protects the liner from sharp debris, rocks, and uneven ground that can cause slow wear or punctures from below — inexpensive insurance under a liner that's otherwise costly to replace early. Keeping the water chemistry balanced matters just as much: chlorine, pH, and alkalinity that swing outside their target ranges can dry out, stain, or weaken vinyl before its time. Between a floor pad, balanced water, and a liner thickness suited to your climate and use, you can push toward the long end of that range instead of the short end. The liner is just one piece of what's needed once the frame is up — see our guide to completing your above-ground pool setup for the pump, filter, and ladder that round out the kit.
Frequently Asked Questions
What's the difference between overlap and beaded liners?
An overlap liner drapes over the top of the wall and is held by a plastic coping strip, leaving the folded edge and strip visible above the waterline. A beaded liner has a formed bead that snaps into a track around the wall, sitting flush with no visible strip for a cleaner look. Overlap is generally the more economical of the two; beaded liners are easier to remove and replace later.
What is a unibead or J-hook liner?
A unibead liner has a J-hook edge that lets it hang over the wall like a standard overlap liner, but a thin strip can be peeled away to expose a bead and convert it to a beaded-style fit. That makes it the most versatile of the three liner types, since it works on pools set up for either overlap or beaded hardware. It's a good choice whenever you're not certain which hardware your pool uses.
Is a 20 mil liner better than 15 mil?
A 20 mil liner is thicker than a 15 mil liner, which generally means better resistance to punctures, abrasion, and UV breakdown, plus a more solid feel underfoot. It typically costs more, so the tradeoff is durability versus upfront cost rather than one being universally better. Households that want maximum durability can step up further to a 25 mil liner.
How long does an above-ground pool liner last?
A typical above-ground pool liner lasts roughly 8 to 15 years with good care. A floor pad underneath to guard against punctures and balanced water chemistry are two of the biggest factors in reaching the longer end of that range. Liner thickness and sun exposure also play a role.
How do I know what size liner to buy?
For a round pool, you need the wall diameter, such as 15' or 24', and the wall height, typically 52-inch or 54-inch. For an oval pool, you need the length and width together, such as 20' x 12', plus the wall height. You'll also need to match the hang style — overlap, beaded, or unibead — to whatever your pool's top rail or coping system supports.