Hot Tub Shell
This is the most important part of your hot tub as the majority of the other components can be replaced if required.
The most common hot tub shell consists of a sheet of acrylic that is moulded into shape and reinforced with fibreglass, as the acrylic sheet alone is not strong enough to cope with the stresses caused by the volume of water when full. It is vital that the quality of this reinforcing is up to the job or you could end up with problems. Unfortunately checking this is very difficult to do - especially if foam is used to add an insulating layer to the shell. Poor quality reinforcing or lack of bonding to the acrylic sheet can also lead to delamination which can result in cracks or blistering of the acrylic.
There are other materials used including ABS backed acrylic, some styrene-based shells and one or two manufacturers that make use of the original hot tub material - wood.
The amount of foam used in the construction will have two major effects:
- it will keep operating costs down by insulating the hot tub shell from heat loss
- it will determine how easy or difficult a repair is, should the plumbing need to be accessed
Some foam insulation is provided in layers making its removal simpler, should maintenance or repairs be necessary to the pipework or substructure.
The hot tub shell or even the shell surface will usually have a separate warranty to the rest of the hot tub so check exactly what is and isn't covered and also what responsibilities you have with regard to maintenance of the various components to keep the warranties valid.