Saunas (both indoor and stand-alone outdoor buildings) are becoming increasingly popular in Canada. As more Ottawa homeowners design and build saunas, we field many calls asking for recommendations on the best wood to use. Our go-to suggestion is western red cedar, but if someone wants a different species, thermally modified wood is a unique option. 

When choosing wood for a sauna, there are a few things to keep in mind: 

• Heat Retention: You need to choose a wood that doesn’t retain too much heat. Very dense woods hold heat and can be uncomfortable to sit on. 
• Dimensionally Stable: There are extreme heat and humidity fluctuations in saunas, so the wood needs to be durable and resistant to warping and rotting. 
• Appearance/Aroma: A sauna should have a calming atmosphere, so the appearance and aroma of wood are important.  

Using the above considerations, it’s no wonder that western red cedar and thermally modified wood are our go-to recommendations! 

Western Red Cedar Wood for Saunas 

Heat Retention: Cedar is a low-density softwood. As such, it doesn’t readily absorb heat, so it provides a comfortable surface for sitting (or laying on!). 

Dimensionally Stable: Cedar is known to be resistant to warping and cracking, which makes it a perfect option for saunas. The extreme temperature and humidity swings will not negatively affect cedar like other species. 

Appearance/Aroma: There’s no denying that cedar has the classic sauna look. It also has a pleasant aroma, especially when heated.  

A customer’s indoor sauna made with our select cedar.

Thermally Modified Wood for Saunas 

Thermally modified wood is lumber that has been subjected to pyrolysis – heating wood to over 400°F (180 °C) in the absence of oxygen. This process creates a final product that is perfect for use in saunas. 

Heat Retention: Thermally modified wood absorbs heat without overheating, creating the perfect atmosphere for a relaxing sauna.  

Dimensionally Stable: The thermal process stabilizes wood, so it’s less vulnerable to shrinkage, warping, and cracking. The high heat also removes any natural sugars from the wood, hindering any mold or fungus growth. 

Appearance/Aroma: Sustained exposure to high heat during pyrolysis amplifies the wood’s natural colour, mimicking an exotic wood appearance. There can also be a coffee or smokey aroma from the wood when heated. 

Whether you choose cedar, thermally modified wood, or another wood species, remember to keep these final points in mind: 

• Make sure to attach boards in a way that hides the fastener head. A nail will heat up in the sauna and potentially burn the skin. For this reason, many people choose tongue and groove boards for the wall. 
• Do not apply paint, varnish, or stain to the interior of the sauna.  

Did you know that we offer free product consultations? Book an appointment with one of the knowledgeable sale staff to discuss your sauna project. Get started by filling out the form below.