How to build a sauna

HOW TO BUILD A SAUNA

By Gavin Deriu

Background:

This how-to guide is a bit more ‘niche’ because not everyone would go to the trouble of building a whole sauna, and if they did it usually requires the help of a builder or some kind of sauna installation specialist. Plus it’s a lot more expensive than most of the DIY jobs I’ve blogged about.

But if you’ve ever wondered how a sauna works or what goes into its construction, this guide will still be useful. Sweating it out in a sauna is a great way to relax and revive, including getting rid of a lot of toxins in your body.

STEP 1:

Find yourself a builder. Failing that, you can probably call upon one of your carpenter mates to help you. I say this because building a sauna is a job that is very construction-heavy and involves a lot of woodwork. It’ll also require some electrical work. Fortunately, my Dad’s a builder so we had no shortage of expertise. Bonus: he also has a ute, which is necessary to carry the timber and other materials.

STEP 2:

You’ll need to purchase cedar timber panels for the walls, ceiling and floors. This will require a lot of estimating, so you might want to consider buying a second-hand sauna or a pre-measured sauna set to take away the guess-work – much easier!

Another consideration is whether your sauna will be free-standing or built-in somewhere under/attached to your house. We chose to fit our sauna underneath our rear deck, next to an existing bathroom/changeroom for the pool.  

STEP 3:

This is where you’ll need an electrician for some simple electricity work, namely to run wires and a switch for the light and also to run a power line for the heater that will go in later.

STEP 4:

Since our sauna was surrounded by an existing structure, in this step we used timber beams (like the type that sits behind your house’s inside walls) to build a frame for the sauna. In later steps, the cedar panels will be nailed to this frame, so make sure it’s all straight and level!

STEP 5:

A sauna works by getting water and pouring it over extremely hot rocks, which causes hot steam and increases the temperature. As a result, there is a lot of moisture and humid air involved. Therefore your next step is to lay INSULATION around the frame (this keeps the heat in) and also to lay what is called SISALATION which is a material that prevents moisture from escaping.

These two materials will ensure that (a) your sauna keeps the heat in, and (b) that moisture doesn’t escape and do damage to the surrounding timber and electrical wires.

STEP 6:

Now it’s time to nail all the cedar panels to the frame to make the walls, ceiling and floor of your sauna. This is a big task, and it could take a few days because it requires a lot of measuring, cutting and levelling of timber (unless you bought a pre-made sauna set, in which case it should be all measured up and ready to go).

You might also want to put some kind of lip/cornice to neaten up the edges, as you can see in the photo below.

STEP 7:

Time to add a door. We were lucky because we already had a pre-made door, so it was just a matter of lining it up and fixing it into the empty hole that we had left in one of the walls. The door doesn’t have a lock, and should always open outwards. It’s also necessary to have a glass window in the door for safety reasons.

STEP 8:

At this stage, your sauna should be an empty timber-panelled room. You don’t want to sit on the floor, so it’s now time to build some seats. We used horizontal panels and made the seats span from one wall to the other, then branching off in an L-shape.

STEP 9:

Time for the finishing touches... Firstly you’ll need a heater. This is a device that contains rocks in it, and it heats up those rocks when turned on. It’ll need to be connected to the electricity wires you had put in earlier on.

Another final touch is the light (must be a special kind of bulb to resist the moisture, and preferably protected by timber shutters like this).

STEP 10:

Now your sauna is ready! Put a temperature and humidity gauge up on the wall because this is necessary so that you can keep the room at an ideal temperature. Remember that a sauna is most effective if you use it for no more than 10 minutes at a time – so don’t spend too long in there. Also keep hydrated!