Fact #4 - What makes a pool liner slippery?

"What makes a pool liner slippery?", is a question I'm sometimes asked. The query usually arises when a liner has just been replaced. The pool owner comments on how the new liner is more slippery than the old one, and wonders why. Other comments I've heard, relate to the surface texture of the liner and what difference this can make. There are several factors which contribute to a slippery feel on your pool liner.

Let me explain....

Firstly, the texture of the liner surface is known as the embossment (or emboss for short). All pool liners have an emboss. Some have a "matt" emboss, which takes the shine off the surface of the PVC. Some have a heavier texture like a leather grain, and others have a diamond or "fishnet" pattern. For all non-reinforced pool liners, the emboss does four main functions.

1. It stops the PVC fabric sticking to itself when on the roll.


2. It covers up air lines and streaks in the PVC surface that are caused by the manufacturing process.


3. It gives a certain look and feel to the PVC


4. It can add to the thickness of the PVC

The emboss you find on swimming pool liners does not have any affect on the slipperiness of the liner when it has been installed in the pool. It is used because of how it makes the fabric look.

The vinyl fabric itself can contribute to slipperiness, but usually only when it is new. Flexible PVC has certain additives in the mix to assist with the rolling and processing during manufacture. These are called "lubricants" and affect how slippery a liner feels when it is first installed. After 2 or 3 months, these lubricants "wash off" the liner surface and the liner appears to have much more grip underfoot.

Pool chemistry plays a significant factor in the slipperiness of liners and all pool surfaces. Build up of calcium on old liners adds extra grip underfoot and this can exaggerate the difference in grip between an old and a new liner. The most common culprit of slipperiness is algae. A fine layer of algae on the pool surface, while not clearly visible to the eye, is very slippery. Therefore one of the first actions to consider if you find your pool liner to be slippery, is to check the chemical balance of your pool.


In conclusion, if you find your liner to be more slippery than expected, check the chemical balance of the pool and ensure this is correct. If it is not due to the chemical balance, but your liner is brand new, then you will find after a few months the liner should have more grip under foot.

Fact #3: Wrinkling of Liners in Indoor Heated Pools

The strangest phenomenon I’ve seen in my thirty-something years in the liner business is "wrinkling liner material caused by indoor heated pools". If you read my recent blog about chemical levels you would conclude that this problem relates specifically to imbalanced pool chemicals, but this is not the case from my experience.

It first started in the 80's when a customer contact us to say the pool liner in their 50 metre long pool, had grown about one whole metre in length. I almost didn't believe them, so I went to see it for myself.

When I inspected the liner, sure enough, there were wrinkles and folds of liner all over the floor of the pool. It looked like the reverse of a dry creek bed, instead of open cracks, these were folds of PVC in a random crazed pattern. After a lot of investigation by the fabric manufacturer, the conclusion was that this phenomenon was a reaction to a pool environment that was made up of the following factors:
· Indoor
· Heated
· Commercial use (like a training pool or public pool)

Another case which proved the validity of the study result to me, was a school pool in a cold climate. It was built as an outdoor pool and used for two years without any noticeable liner growth. Then, the school decided the pool would get more use if it was covered, so a new building was built over the top of it. It became an indoor heated pool and within one year, the liner had grown to have large wrinkles all over the floor.

How can this be? What happens is, under these conditions, the PVC absorbs water and therefore expands. The expansion becomes visible as wrinkles and there also appears to be deterioration in the strength and flexibility of the PVC; in severe cases I have seen cracking along the creases.

Different solutions were trialled like, maintaining a level of cyanuric acid (not normally needed for an indoor pool), using a lacquered fabric, using a printed fabric, yet nothing solved the problem and so it was concluded that unsupported PVC was not suitable for pools with these environmental conditions.

The fabric manufacturers’ no longer provide a warranty for their PVC when used for this application and so it used at the risk of the Purchaser.

There are plenty of domestic pools that are heated and located indoors which do not show any problems, but many of the commercial pools under these conditions will exhibit the considerable wrinkling caused by this phenomenon.