Choosing the Best Liner Thickness

When you are choosing a liner for your pool, liner thickness is one of the choices you will need to make.

In-Ground Pools
The two choices for in-ground pools are 20 mil and 27/28 mil. For the 27/28 mil, some companies call it 27 mil, while some call it 28 mil. I was told that it is technically 27.4 mil, so some companies take the liberty of rounding it up to 28 mil. In any case, it's basically the same thing!

There are three extremely important factors to take into consideration here: pool shape , weather , and pool corners . Many of these things have to do with a little bit of physics. Without getting too far into the technical details, it's important to discuss pliability. I'm a nuts and bolts kind of guy and when it comes to pool liners, I want the best fit possible. A thicker liner has advantages and disadvantages, but a major disadvantage we see with thicker liners is decreased pliability.

In-ground pools come in all different shapes and sizes and they also tend to settle and shift with the ground over time. This is why it is so important to have your pool professionally measured and to take into consideration the opinion of the professional in terms of liner thickness. The shape is important: if the pool has a lot of tight, intricate turns, it's better to go with a 20 mil liner in order to achieve a better fit. I cringe when someone with 90-degrees corners wants a 28 mil, especially in cold weather. The thicker liner just isn't as pliable as the 20 mil.

The weather is also a factor to consider when choosing a liner thickness. Early spring and late fall in the Northeast tend to be cool. Vinyl liners are not as pliable in cool weather. So what can you do? The Liner Specialists can work with a 28 mil liner in cool weather if the homeowner chooses a dark colored liner and the pool is in a sunny backyard. The UV rays from the sun are also extremely important. That's why 28 mil is not always the best choice and a pool liner professional's opinion can help to guide you toward the best choice for your pool.

If you want to install your liner in cooler weather conditions, there is a great choice available to you. Aqua Max by Merlin Industries contains a proprietary formula, 20 mil thickness with extra UV coatings, and greater chemical resistance. I love it for great fits. My liners last more than the average liner int he New York metro area, with an average of 13-15 years and sometimes even longer! I sold a repeat customer last year and he told me that he was ready for a new liner after we installed the old one 21 years ago! I was told in a seminar I attended that the average pool liner lasts 8 years, which I find to be unacceptable. One of our biggest competitors tends to make their liners too tight, which thins the vinyl and shortens the life of the liner. Proper measuring is my forte, what I am most accomplished in and what I hope to impart to other professionals when I teach for the Northeast Spa & Pool Association (NESPA).

Above Ground Pools
As far as above ground pools are concerned, there are a lot of myths we try to dispel when it comes to liner thickness. We custom measure some of our liners for pools like Esther Williams, Johnny Weissmuller, Wilkes, Kayak or any other pool that doesn't conform to stock sizes. This procedure is very unconventional and a little more expensive, but makes for a great fit.

We will custom measure using in-ground 20 mil or 28 mil material or with a 19 mil wall and 18 mil floors. Merlin Industries is the only manufacturer that I know of that uses this combination. Thicker is more durable, but the right fit is where the longevity of your pool liner is determined.

Most of the above ground liners are thin, although most manufacturers call their thickness 20 mil. This is because they emboss them. Embossing is the process of checker-boarding extra material in the sheet of vinyl. So a vinyl that is 13 mil or 15 mil with embossing would mic (pronounced mike ) out to 20 mil. These liners are also recycled, which makes them vulnerable to pin holes.

There is another misnomer that people use frequently: calling the thickness of a liner its gauge . This is incorrect. The correct term for liners is mil, although this is not short for millimeter . It is the term that represents 1/1000th of an inch. Therefore, 20 mil = 0.020 inch and 27 mil = 0.027 inc. To help you with conversions, 25 gauge (an approximate value) ~ 20 mil and 34 gauge is ~ 27 mil.

If you need help selecting a vinyl liner for your pool, call The Liner Specialists today!