There is a difference between plastic and plastic in a pool
When the decision to invest in a pool is approaching, it is easy to assume that most pool constructions are equivalent, apart from obvious variations in size, color, and shape. Many initially focus on the aesthetic, how the pool harmonizes with the garden's design, which is of course an important aspect. However, it is of crucial importance to also carefully consider the material choice. There are significant differences between different plastic types, differences that can be more extensive than one might first suspect.
Polyvinyl chloride (PVC)
A significant portion of the pools sold in Sweden today are lined with PVC liner fabric, despite the Swedish Society for Nature Conservation advising against this material. A primary reason is that the plastic's raw material can potentially be hazardous to health. Additionally, phthalates are added to achieve the desired softness in the plastic. These substances are not only hormone-disrupting but have also been shown to be carcinogenic. Since they tend to migrate from the plastic and leak into the water, they can thereby be absorbed by the body.
As a consequence of this, the European Union introduced a ban in 2015 on the use of these substances in the manufacturing of PVC within the EU. Therefore, modern PVC materials produced within the EU should no longer contain phthalates. However, it is important to note that legislation outside the EU is not as strict. It is therefore crucial to carefully examine where the ordered liner fabric originates and its manufacturing date. Today's PVC production within the EU is regulated, but sales are not regulated to the same extent. This means that PVC manufactured before 2015, or PVC from countries outside the EU, can still be sold and used in pool manufacturing. Therefore, be critical and ask your pool supplier specific questions regarding which material will be used and its origin.
Polypropylene (PP)
Instead of lining the pool with a PVC liner, many today choose a PP pool. This pool is delivered as a pre-cast tub that is lowered into a prepared space in the ground. The plastic used for these pools is usually polypropylene (PP), hence the name PP pool.
Polypropylene is a robust and relatively environmentally friendly plastic that offers excellent insulation. This reduces heat loss through the pool tub, helping the water maintain its temperature for a longer time. The material is lightweight but at the same time very strong and homogeneous. It therefore withstands scratches well and has a long expected lifespan.
This plastic can be through-colored and does not give a typical 'plastic' impression when the pool is cast. Additionally, it is easy to shape, allowing for ordering integrated steps, seating benches, or other custom details in the pool.
Unlike PVC plastic, PP plastic withstands high temperatures without undergoing changes. In a PP pool, you can therefore swim in temperatures over 30 degrees without the material being damaged. The only change that may occur over time is that the surface may become slightly matte.
Fiberglass (polyester)
Fiberglass, also known as polyester, is another plastic used to cast ready-made pool tubs. The casting technique often results in softer lines, and the material gives a glossy, almost glass-like surface with a certain shimmering effect. This creates a different visual impression compared to the PP pool's more elegant design, which is of course a matter of personal preference.
The tub is constructed with multiple layers of fiberglass, unlike a PP pool which consists of a homogeneous material. The number of layers and the specific materials used in the different layers affect both the price and durability. A pool with fewer layers and cheaper materials may have a lifespan of 4-5 years, while a more premium model can last up to 25 years. This can be compared to a PP pool, which can have a lifespan of up to 45 years.
Another factor to consider regarding fiberglass pools is the risk of so-called 'blister plague'. Fiberglass is not completely waterproof. When water penetrates through the different layers, moisture forms that can lead to mold growth. Over time, the mold develops gases that form bubbles that expand and create bulges in the fiberglass – a phenomenon called blister plague.
Another problem with fiberglass's lack of density is that water can remain in the material when the temperature drops. We all know what happens to water in winter – it freezes. Here arises the next risk: when water has penetrated into the layers and stays there, there is a risk that the material will freeze and break from the inside. This is difficult to prevent because the water migration cannot be controlled or stopped. The risk decreases, however, if the manufacturer uses denser materials. It is therefore important to carefully investigate what material the specific fiberglass pool you are considering is made of, as there can be significant differences between different fiberglass pools.
As you now understand, there is a clear difference between different plastics, and there is every reason to carefully consider your choice from several perspectives. With this overview, I hope you now have more information to base your purchase of a pool on. The price is of course always an important factor, but there are also other aspects to consider. Once you have decided to invest, it can be reassuring to make an active decision that allows you to feel secure and sleep well at night.
