THE HISTORY OF THE WORLD OF RIGID POOLS
If we talk about rigid pools for a moment, harking back to 1982 when there were only pools made of fibreglass. There were good and bad brands, as fibreglass pools are products that require manual skill to produce. But on the whole if the pools survived the delivery and installation process, they generally lasted longer than their owners.
Then came pools made from ABS and HDPE: more robust in storage at the garden centres and vastly cheaper. These seemed like a shotgun blast to the head of a business that was just beginning to boom.
They were a moulded product, which although they could be produced in vast quantities at the touch of a button, their limitation was in the physics of making moulds and the sizes of the sheets of raw material.
Once it was realised that you only could get small pools from these materials, fibreglass re-emerged into a new niche, offering highly durable pools that were larger and deeper than the plastic competition … A particularly attractive proposition for people interested in creating water gardens for fish, even Koi carp keepers (especially when they were pandered to with the dimples and grooves built into the shape to take the pipe work and fittings for the very best type of biological filtration, when it is ‘gravity fed’ from a sump in the bottom of the pool.)
Rigid pools represent ‘the cheap and cheerful’ end of the market on a par with the moderately priced flexible liners in terms of price per square foot of surface area and if there is a shape and size that suits the space you had in mind they are worth considering. They are easy to clean because of their smoothness, which on the other hand gives them a clinical look that only weathers to an extent required for a suburban patio pool. Even fully laden with plants could never be mistaken for a ‘natural feature’, and because of their size they can easily look lost or out of place if there is enough room in the garden for other distractions.
If you are looking for something to waterproof your hole in the ground the way you have designed it and if you want it to look natural or to look purpose built with brick or stone facing, not just outside, but inside as well then a flexible liner is imperative. If you have the intention of creating more than 6 square metres of water surface and a depth that suits you, the plants and the fish, again you must use a flexible waterproof sheet of some kind.