A solid foundation for your spa – what you need to know

Your spa, swim spa or plunge pool needs a solid, flat, level foundation. lt must be positioned to allow for adequate service access on all sides of the spa. Learn more in this article.

spa foundation hero

Spas and swim spas do not have legs, instead they have flat, integrated bases that spread the weight of the load across a larger surface area.

If the foundation for your spa, plunge pool or swim spa is inadequate – it may shift or settle after the spa is in place. This can cause stress to the shell and cabinet, which will void the warranty.

Always consult your building professional for advice about your specific circumstances. All work needs to be carried out within the guidelines of your local building regulations. Refer to your spa model's technical sheet for weights and dimensions. You can download the techpack from the specifications section of the product page for your spa model on the Spa World website.

What foundation are you using for your spa?

The five most common foundations for spas are:

  1. Concrete slabs
  2. Paved surfaces
  3. Inground spa pits
  4. Wooden decks
  5. An existing surface

Depending on the foundation you decide on, there are some rules of thumb to follow – as we explain below.

Existing Foundation

If you are planning on using an existing foundation, you will need to make sure the foundation is adequate to support the full weight of the spa.

We recommend consulting with a building professional to determine the structural integrity of your existing foundation and to help you if the slope is an issue.

If there is significant slope in the foundation, the spa water will not be level in the spa and this can damage the shell.

Here is an example of one solution for a sloping foundation surface:

pad slope diagram

1. Concrete Slabs

For portable spas up to 3.5m they will need a minimum 100mm reinforced concrete slab.

Click the button below to view generic spa slab design for portable spas.

For swim spas and spas larger than 3.5m we recommend a 150mm slab with 2 layers of reinforcing mesh.

Click the button below to view generic spa slab design for swim spas and portable spas larger than 3.5m

2. Paved Surfaces

If you are installing onto a paved surface, you must ensure that your area is flat or level and capable of supporting the filled weight of the spa.

If the surface is not flat or level or capable, it will cause stress to the shell that could result in damage to the shell which would not be covered under warranty.

3. Inground spa pits

If your spa or swim spa is going to be installed in a pit, you must consult with your local builder or contractor regarding drainage. Most likely a sump pump will be required to avoid flooding.

To learn more on how to install a spa or a swim spa in a deck or pit, including the sinking requirements, please click the button below.

4. Wooden Decks

Decks must be designed and built to local building regulations by a registered builder.

5. Existing surface

If you are installing the spa onto an existing surface, you will need to consider the amount of fall that surface has.

We do not recommend installing spas or swim onto a surface that has more than 20mm of fall across the length of the spa. You may need to talk to a builder about wedging the spa in order to keep it level.

Is there adequate drainage for flood protection?

All spas and swim spas must have adequate drainage around the foundation to ensure that the spa or swim spa is not flooded.

Consult your builder or landscaper. Flooding is not covered under your spa warranty.

Can the spa or swim spa be accessed for service and maintenance?

It is crucial that all cabinet panels around your spa can be accessed and removed for servicing. Specifically, careful consideration is required when installing your spa in a deck.

When it comes to warranty inspections, servicing and maintenance – it is your responsibility as the spa owner to ensure the spa’s machinery and equipment can be easily accessed.

What are the key electrical considerations when planning my spa or swim spa foundation?

If you are choosing to run the power or heat pump supply through your spa foundation, please click the button below for a full list of items that you will need to be aware of.

Need more help?

We hope this information has been helpful. If you have any questions or concerns about your spa or swim spa installation, please contact your Spa World concierge.

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