DIY Outdoor Sauna Project For Your Backyard

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Saunas have long been tied to a myriad of health benefits. 

Beyond pleasure and relaxation, studies show having a sauna can help relieve stress and lower blood pressure.

If you love sauna and you want to incorporate it into your everyday life, you may as well make your DIY outdoor sauna. 

It’s fun and rewarding.

DIY Outdoor Sauna: Steps to Build

Outdoor saunas usually require a building permit. 

Remember to check all the regulations before building or installing a sauna.

Step 1: Pick a Location

Similar to outdoor kitchens, location is of major importance in outdoor saunas.

Most people choose to install their outdoor saunas at a cottage or by the backyard pool. 

Pick a level ground with enough space for a 7-foot by 6-foot box.

If you’re using a wood-burning stove, you may want to build your DIY sauna a bit farther from your house to lower the risk of fire hazards.

When picking a location, you should also consider the size of your sauna.

Ideally, an outdoor sauna should house two or three people at the same time. 

Thus, it should have dimensions of 4″ x 6″ to 5″ x 7″ the least.

Last but definitely not least, choose a location where you get the best views possible. 

This should ensure an ultimate sauna experience.

Step 2: Choose Your Materials

Wood is the most common material used for saunas. 

Most people build saunas out of cedar because this wood handle moisture well.

It’s also very stable and resists warping due to heat and changes in humidity.

Plus, it lasts longer.

Other good options are basswood, eucalyptus, thermo-spruce, and other softwood.

They are quite expensive but they make beautiful saunas that stand the test of time.

Cedarwood is a bit more expensive, but it smells great and is naturally resistant to rotting. 

Use cedar on the siding and exterior parts, as well as the groove on the inside. 

For the rest of the building materials, you can use leftover wood from your other DIY projects or some inexpensive pine wood.

Step 3: Gather the Supplies

To build an outdoor sauna, here are the things you need:

  • About 100 pcs of 1500X80X50mm wooden beams
  • Concrete slabs
  • Gravel
  • Decking boards and wooden struts
  • Bitumen roofing felt
  • 5X10mm steel rods with washers and nuts
  • Sauna door
  • Heat source
  • Wood glue
  • Wood screws
  • Tools like an electric drill, cutting saw, hammer, knife, flame scarfing device, etc.

Alternatively, you can purchase a DIY sauna kit that includes everything you need.

The great thing about them is that the materials are already pre-cut.

All you need to do is assemble the parts.

diy outdoor sauna at home

Step 4: Start Building

Now, this is the fun part, but also the most daunting.

Below are the steps to build a DIY outdoor sauna:

1. Build the Foundation

First of all, you’ll need to pour a concrete foundation for your sauna.

Hire a builder if you need help in this step as it can be a tricky process.

Also, since it’s the foundation, you want to do it right.

If you decide to do it on your own, you can go for a simple foundation.

Just make sure that all the slabs are at the same height and level.

2. Build the Flooring

You can use decking planks for the flooring as they are both durable and beautiful.

Your flooring should behave the size of the length and width of your frame.

Screw the decking planks on the frame, then cut them in size.

3. Frame the Walls

Next, you have to frame the walls and roof.

Professional help also comes in handy in this part.

Consider building a drain for easy cleaning of your sauna.

4. Insulate

Don’t forget the insulation.

Unless your outdoor sauna is barrel-style, you will need insulation.

There are many types of insulation but fiberglass is the most recommended for outdoor saunas.

Choose a fiberglass insulation material with R-values ranging from R-2.9 to R-3.8 per inch. 

Note that both the walls and roof should be insulated.

5. Build the Sidewalls

Drill holes at one of the wood beams.

The hole is for the steel rod which will be used to align the beams.

The hole needs to be rilled in the middle width of the beam. 

For example, if your beam is 50mm thick, you should drill the hole 25mm away from the end of the beam.

Screw the first row of wooden beams on the floor and make sure that each corner has a steel rod inserted.

Stack the next layers of the walls using steel rods and wood glue.

6. Install the Roof

Installing the roof is the same as the sidewalls, but this time you won’t have to drill holes.

Instead, simply screw the first beam on top of the walls and connect the other beams using wood glue.

Screw the final beam on top of the wall.

Next, install waterproof sheeting, such as asphalt or bitumen felt on your wooden roof, and a flame scarfing device to glue it to the wood.

7. Install the Door

You can use a full wooden door or a heat-resistant glass door for your outdoor steam room.

If you want it more modern, you can use a door made from wood or metal with glass inserts.

When purchasing a sauna door, make sure that it meets the fire safety requirements.

Also, avoid a door that’s too large.

This is because you’re striving to maintain the heat in the room for as long as possible. 

Experts recommend installing lower doors in the sauna but it’s fine if you want a traditional-sized door.

The most important thing is to make a threshold, that when opening the door, the cold air would not enter your sauna and cool it down.

Step 5: Choose a Heat Source

To warm your outdoor sauna, you can choose among wood, gas, electric, or infrared heat sources.

If you want the traditional sauna feels, wood-burning is the way to go.

However, if you’re after convenience, electric and gas saunas are easier to maintain.

Some saunas use infrared light to create heat.

It’s the most efficient heat source because infrared is quick to heat up and uses considerably less electricity.

Step 6: Decorate Your Sauna

If you have a beautiful garden view at home, it’s nice to have some windows.

Use a double-pane window and install it away from your heat source.

Of course, you need a bench where you can comfortably sit.

Lighting is important too as it sets the mood. 

Use heat-resistant lights for your sauna.

A small cabinet where you can place your sauna essentials is another great addition, plus a space where you can place little trinkets.

Don’t forget to install hooks on the wall for your towels, robes, and clothes.

If your sauna is big, you can place a shower inside. 

Otherwise, you can have an outdoor shower nearby for convenient pre and post-rinse-off.


If you’re tight on interior space but have a little extra room in the backyard, a DIY outdoor sauna is perfect for you.

Building your sauna is a lot of fun and you don’t need much to get started.

Before anything else, choose a nice spot on your lawn or backyard that is roomy enough for the size of sauna you want.

Next, decide on the materials.

For that instant sauna feels, we recommend timber made from cedar or equivalent wood.

Then, gather the rest of the supplies and tools needed.

Building an outdoor sauna can be a bit complicated but it’s extremely rewarding once you see the outcome.

Be as creative as you can be and make your outdoor sauna a reflection of your personality.

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