How to select your hot tub base

Posted by Nick Clamp in Hot Tub Installation Guides on 26th October 2020

Like a strong foundation for any decent home, it is important to ensure your new hot tub has a solid base location. Before the hot tub installation process is conducted you need to draw up your plans to create an ideal hot tub base for your hot tub to be sited.

With the accumulation of many decades of knowledge the team here at WhatSpa?  know how critical it is to conduct the correct research and implementation of hot tub ground work. This will then provide many years of satisfaction while enjoying your top quality hot tub experience on a regular basis.

What are the benefits of a solid hot tub base?

While you are conducting hot tub base research you should be aware that many elements of the installation process must be organised and completed ahead of delivery, preferably by a WhatSpa? Approved supplier. Major delays to using your hot tub for the first time may be caused by neglect of essential pre-delivery hot tub base planning; which you will find comprehensive guidance on within a dedicated feature of the latest edition of WhatSpa? that has a complementary Retail Directory with listings of your local hot tub showrooms that supply the best hot tub brands in the UK market with WhatSpa? Best Buy Award-winning models.

Attempts to conduct hot tub base preparation without this knowledge or experience, especially power supply preparation and electrical work, could lead to disastrous consequences. Your hot tub could be damaged or may not be able to be repaired or serviced correctly if it has been semi-sunken or fully-sunken without provision of access.

As part of your ground work, for example, you will have to ensure that any outdoor cabling to create a dedicated power supply to your hot tub base structure for the operation and control of the hot tub functionality should be protected from damage by either laying protective ducting (pvc pipe) below ground or by utilising steel wired armoured (SWA) cable. The best policy is to leave a tail of SWA cable from an appropriate isolation switch that is sufficiently long enough to feed into the hot tub cabinet and reach the load box within the hot tub equipment bay.

Solid hot tub base preparation will pay dividends, and if you link up with a specialist WhatSpa? Approved supplier you should gain expert advice and guidance along every step of the process; especially as you have to take into consideration the weight of your new hot tub when it is fully loaded with water and people in all of the seats. If your supplier is not prepared to provide this guidance and conduct a professional hot tub site survey then move on and find another respected dealer who will offer this essential service provision.

A professional dealer should have the experience and product knowledge to indicate the best locations for a hot tub base and provide advice and guidance on some of the most common hot tub bases. While you are conducting research of the best hot tub brands , you should be considering some of the traditional and increasingly popular hot tub bases.

What are the hot tub bases available?

To get you up and running with this research process here are six hot tub bases to consider:

  1. Concrete
  2. Decking
  3. Gravel
  4. Paving stones
  5. Hot tub pads
  6. Plastic tiles


This is by far the most common method of providing your hot tub with a solid and sturdy base foundation as the level concrete platform will provide durability for many years to come. If you do opt for this hot tub base method then it is best policy to ensure that the concrete is at least four inches thick and avoid any slopes by ensuring that the concrete is level. Hot tubs that are semi-sunken or fully sunken into a concrete pit or within a concrete landscaped feature will require the provision of access for future repair and servicing work.


Photo © Urban Cedar

During the past decade there has been an annual increase in the use of decking as a hot tub base. Rustic hot tub projects, with dedicated decking material for semi-sunken or fully-sunken hot tubs, have grown in popularity and many stunning designs with decking have been featured in WhatSpa?.  As a rule, the cross-members supporting the deck should be 4” x 2” and no more than 18” apart. It is also critically important to ensure that access to the hot tub can be achieved by a professional hot tub engineer. A section of decking that can be removed specifically for this process may be an option, without having to rip out large sections of the decking in the future. So, as with sunken concrete installations, it is important to put this element of the pre-delivery work in your plans.


Gravel bases have natural durability and can be an alternative method to an actual concrete base but, unlike concrete, there could be initial delivery problems of hot tub damage or future irritations of hot tub movement when the hot tub is filled with water and people. Without a dedicated pit structure for the gravel, such as a specialist hot tub pad, your gravel base may become problematic. This base foundation for your hot tub should be level and secure.  As well as causing potential damage to your hot tub, gravel around your hot tub can also cause injury to your feet as you enter and exit your hot tub.

Paving stones

Photo © Chiswell Leisure

Paving stones are another base foundation method that can provide a solid base for your hot tub. This base structure has the extra benefit of being more flexible in the aspect of design and implementation. Different colours and designs of paving stones can be applied to blend in with other elements of your hot tub project and your garden surroundings. It may also help to prevent grass from entering your hot tub if the paving stones are extended further around the hot tub and as part of a dedicate path, rather than just under the hot tub itself. It can be a problematic base, though, if the paving work is not conducted properly to ensure that all the paving stones are level and fitted together correctly in a way to prevent them from moving apart or the danger that they will subside once the hot tub is in position due to the ground below not being prepared properly.

Hot tub pads

In the last year there has been a rise in demand in the inflatable hot tub market and as a result there has been an increase in sales of hot tub pads. These hot tub pads are mostly an extra cost, but they will prevent hot tub damage and provide extra cost savings with greater insulation properties. Some hot tub pads have been designed to be the perfect fit for certain inflatable hot tub models that do not necessarily require a thicker pad. Traditional hot tubs, with some larger designs having water capacity over 2,000 litres will have a greater weight that may require thicker hot tub pads. They are an ideal based protection purchase to eliminate damage from debris and rough surfaces, while also providing improved heating efficiency. Yet they may have deterioration or odour problems caused by the constant contact with water if they are not of a high quality.

Plastic tiles

Pre-fabricated plastic tiles have been launched to the market to provide owners with another hot tub base option. These may be the perfect solution if you require greater flexibility and bespoke design elements.  Individual colour schemes can be chosen to provide the base to match the surroundings of your hot tub or a specific design theme. There are now designs that incorporate water resistant LED lighting and this may provide you with an additional safety element while utilising your hot tub in low light or darkness. If you are looking for environmentally-friendly options than seek out weatherproof designs that have been manufactured from 100 per cent recycled plastic.

Power supply

A critical element of your hot tub foundation and base preparation is the provision of a suitable electrical supply to operate your new hot tub purchase. Many WhatSpa? Approved suppliers will have their own professional electricians and installation experts to provide you with the necessary electrical supply advice as part of their pre-delivery services and where possible you should take advantage of this.

It is best practice to conduct electrical preparation and work on any water supply well before you complete your excavating and landscaping work.  If they are not conducting this work then your hot tub supplier should be happy to liaise with your electrical and landscaping contractors to ensure a smooth installation process.

Always check that an electrician is qualified to conduct the work that is required to hard wire a hot tub to your property. In January 2005, the Government introduced a new Part P law that demands most electrical work in UK households is only carried out by a ‘competent person’.

This law states that anyone conducting fixed electrical installation work in household in England and Wales must ensure that the electrical installations are designed and installed to protect against mechanical and thermal damage, so that they do not present electric shock and fire hazards to people; and that they should be suitably tested and inspected to verify that they meet the relevant equipment and installation standards.

About the author

Nick Clamp

I am the Editor-in-Chief at WhatSpa? Media Group and my job is to keep you informed about the very latest hot tubs on the UK market... the best job in the world! When I'm not being deluged with press releases and hot tub brochures I enjoy keeping fit and participating in endurance events including triathlons and distance running.

Latest articles from our knowledge bank

WhatSpa? Spring 2021

The UK’s No. 1 Spa & Hot Tub Buyers Guide

This edition is full of spa reviews as well as top tips on buying, owning and maintaining your very own hot tub.

Don’t buy a hot tub or swim spa without it!

Get Your Free Copy