Does an Outdoor Sauna Need a Foundation?

If you're planning to add an outdoor sauna to your backyard or cottage, one of the first questions you'll need to answer is: Does an outdoor sauna need a foundation?

The short answer is yes, an outdoor sauna needs a solid, level and fully supported base. However, that doesn't necessarily mean you need to pour a traditional concrete foundation.

Depending on your property and sauna installation, a suitable base can be made from concrete, patio slabs or paving stones, or a properly supported wood deck. What's most important is that the sauna is level and the entire bottom of the structure is properly supported.

Let's look at what you need to know before preparing a base for your outdoor sauna.

Why Does an Outdoor Sauna Need a Proper Base?

An outdoor sauna is a substantial structure that needs consistent support underneath it. An uneven or poorly prepared base can prevent the sauna from being properly supported and may eventually lead to structural problems.

A proper sauna base helps:

• Keep the sauna level

• Support the full weight of the structure

• Reduce movement and settling

• Protect the sauna from structural stress

• Promote proper drainage around the sauna

• Provide a stable surface for years of use

Preparing the site correctly before your sauna arrives is much easier than trying to correct an unsuitable base after installation.

How Level Does a Sauna Base Need to Be?

For a Northern Leisure outdoor sauna, the base should be level within 1/2 inch across the full length and width of the sauna.

Just as importantly, the entire bottom of the sauna needs to be fully supported.

This means you shouldn't simply place supports at several points underneath the sauna while leaving other areas unsupported. An uneven base can cause the sauna to flex or shift and may result in structural damage.

The goal is a flat, stable surface that provides consistent support underneath the complete sauna footprint.

What Is the Best Base for an Outdoor Sauna?

There isn't one base that's right for every property. Several options can provide the support an outdoor sauna needs when they're properly constructed.

Concrete Pad

A concrete pad is one of the most straightforward options for an outdoor sauna.

When properly prepared, concrete provides a strong, stable and level surface with excellent support across the entire sauna.

Concrete can be particularly attractive for homeowners who are already incorporating their sauna into a patio or larger backyard project.

Patio Slabs or Paving Stones

You don't necessarily need to pour concrete.

Patio slabs or paving stones can also provide a suitable sauna base when installed on a properly prepared and level surface.

The important consideration isn't simply the material you can see. The ground underneath needs to be prepared so that the slabs or stones remain level and continue supporting the sauna evenly.

This is especially important in Canadian climates where seasonal ground movement can affect improperly prepared surfaces.

A Properly Supported Wood Deck

An outdoor sauna can also be installed on a properly supported wood deck.

However, you'll want to make sure the deck is designed to support the sauna and provides a level surface across the entire footprint.

If you're considering placing a sauna on an existing deck, don't assume the deck is suitable simply because there's enough physical space. The structure and load requirements should be evaluated before installation.

Can You Put an Outdoor Sauna Directly on the Ground?

Placing an outdoor sauna directly on grass, soil or another unprepared surface isn't recommended.

Ground can settle and shift over time, and moisture can collect underneath or around the sauna. This can create an uneven installation and expose the structure to unnecessarily wet conditions.

Instead, prepare a stable base before installation and consider how water will move away from the sauna.

Don't Forget About Drainage

The foundation isn't only about supporting the weight of your sauna. Drainage is also an important part of choosing and preparing the installation area.

Your site should provide adequate water drainage so that the sauna's horizontal cedar isn't continually exposed to wet conditions.

Avoid creating an area where rainwater, melting snow or other moisture regularly pools around the bottom of the sauna.

This is particularly worth considering when planning an outdoor sauna in Canada, where the installation will be exposed to rain, snow and freeze-thaw cycles throughout the year.

Can I Put an Outdoor Sauna on My Patio?

Potentially, yes.

An existing concrete or properly constructed paver patio may make an excellent location for an outdoor sauna, provided it meets the sauna's requirements for levelness and full bottom support.

Before installation, check the entire footprint rather than just a few spots with a level. A patio that appears flat may still have a deliberate slope for drainage.

For Northern Leisure saunas, the base needs to remain within the recommended 1/2-inch tolerance across the full length and width.

Can I Put an Outdoor Sauna on a Deck?

A properly supported wood deck can be used as a sauna base, but the deck needs to be capable of safely supporting the structure.

The sauna should sit level and receive support across its entire bottom.

For an existing deck, it's a good idea to have the structure evaluated if you're uncertain about its capacity. Sauna size and weight can vary, so requirements should be considered for the specific model you're installing.

How Big Should My Sauna Base Be?

Before constructing your base, confirm the dimensions of the specific sauna you've selected.

Your prepared area needs to provide proper support across the entire footprint of the sauna. Don't build the base based on an estimate of the sauna's dimensions.

It's also worth considering the space you'll want around the sauna for access, maintenance and drainage when planning the overall installation area.

What Else Should You Plan Before Your Sauna Arrives?

Your sauna base is only one part of preparing the installation site.

Before installation, it's also worth thinking about:

• Access to the sauna

• Water drainage

• Electrical requirements for an electric heater

• Requirements for a wood-burning heater, if applicable

• Custom-installed lighting

• Wi-Fi signal strength if your sauna includes a Wi-Fi-enabled heater

• Clearance and placement requirements

• Local building and electrical requirements

Planning these details before the sauna arrives can make installation much easier.

Do Outdoor Saunas Need a Concrete Foundation?

No. An outdoor sauna doesn't necessarily need a concrete foundation.

What it does need is a solid, level and fully supported