What are the different types of in-ground pools?

When it comes to installing an in-ground pool, the three most common types are vinyl liner, fibreglass and concrete.

They each have advantages and disadvantages.

Vinyl Liner Pools

Vinyl liner pools became popular in the 1960’s. As a cheaper option, vinyl liner pools made owning a pool possible for more families. Over the years different materials have been used to construct the perimeter wall. Initially, timber was affordable and plentiful. As the technology evolved, timber was replaced with a lighter and stronger steel wall panels in the ‘70’s and 80’s. There was a glitch with steel – if the liner leaked, the metal wall panels started to rust, particularly with a salt water pool.

To overcome this, polymer wall panels were developed, providing even greater weight savings, greater design flexibility and resistance to corrosion. Polymer and steel remain the most used materials in wall panels today.

There have been changes in the thickness of the vinyl liners over the years and a drop in popularity compared to concrete and fibreglass in Australia. However, for good reason, vinyl liner pools have stood the test of time.

Concrete

We are almost sure that the Pharaoh’s in ancient Egypt were doing backstroke in concrete pools (ok, maybe not, however they have been around for centuries!). The process then was the same as it is now – dig the hole, lay steel reinforcing bars around the walls and floor to match the desired shape of the pool, cover the bars with concrete to create a concrete shell, and apply a top layer to finish. 

Concrete as a product hasn’t changed a lot in 50 years. The real game changer was a process called Gunite that the pool industry started using in the 1950’s. Rather than shovelling on concrete over steel reinforcing bars; Gunite is a process that uses a pressurised hose to blow the concrete on in layers. Once the right thickness has been achieved, the wet concrete is trowelled to a smooth finish as it still is today. Early concrete pools were then painted to provide the final finish and colour. Today, plaster and tile finishes are used to achieve the final finish.  Outside of this, the construction of a concrete pool is the same today as when your grandparents built a concrete pool. Concrete pools usually offer a 7-year structural warranty which hasn’t increased in several decades.

Fibreglass

Fibreglass has been used since the 1940’s. It’s strong, relatively easy to manufacture, light and durable.

It seems that any innovation relating to pools occurred in the 1950’s as Baby Boomer’s installed pools by the thousands. Fibreglass is no exception with the first in-ground fibreglass pool being built at the same time. In the early days, many people saw fibreglass in-ground pools as inferior to concrete. The designs up to the 1970’s had fewer composite layers, were prone to wearing through after 20 years and the shells were prone to osmosis (ground water leaked through causing small bubbles on the inside of the pool).

By the 1990’s, the “inferior” perception was debunked and the pool-loving public embraced fibreglass pools, leading to an explosion in technological investment. The shells became stronger and more affordable. Today’s pools have multiple composite layers (from the inside out), usually a gel coat top layer, several layers of high strength resin and fibreglass, reinforcing, and a final sealer coat to prevent osmosis. Structural warranties have steadily increased in this time from 10 years to 25 years as an industry standard. A limited number of fibreglass pool manufacturers now offer lifetime structural warranties (our pools come with a lifetime warranty) as their pools have been in the ground for over three decades without problems.