The Strength and Warmth Within: Why a True Finnish Log Sauna Makes All the Difference

Sometimes, you can see quality at a glance.

The two images above tell their own story: on the left, the thick log wall of a Hetki sauna, and on the right, a typical lightweight wall structure often used in outdoor saunas. Both are made of wood, and both can serve their purpose well. Yet they are built in very different ways, and that difference matters. One is solid, load-bearing, and heat-storing by nature. The other, thinner and lighter, relies on added layers and insulation to achieve similar performance, though in many cases those layers and insulation may not even be present.

It’s one of those details worth paying attention to when choosing an outdoor sauna, a seemingly small difference that can have a big impact on how it performs, and more importantly, how it feels.

The Foundation of Quality: Finnish Spruce and Craftsmanship

Hetki is a true Finnish outdoor log sauna.

When speaking about the quality of our saunas, everything starts with the main raw material: logs made of certified Finnish spruce, grown in sustainably managed northern forests.

Finnish spruce, grown slowly in a cold climate, is dense and durable, ideal for long-lasting structures. As a result, when built correctly, a Finnish log sauna is not just a product. It’s an investment in a lifetime of wellbeing.

What Defines a Finnish Log Sauna

In Finland, where log building have centuries of tradition, a log is defined as a solid or laminated wooden wall element with a minimum thickness of 68 mm (approximately 2.7 inches). This definition exists to protect consumers, ensuring that only structures meeting this standard can be marketed or sold as log buildings.

Anything thinner, such as the commonly used 30–40 mm (1.2–1.6 inches) wooden boards used often as cladding, is not considered a log. This standard follows both Finnish building codes and European norms.

In practice, it means that Hetki’s spruce walls meet these criteria in every sense, offering genuine strength, natural insulation, and structural integrity – the very foundation of a real Finnish sauna experience.

That’s what makes a Hetki sauna not just a wooden building, but a genuine log sauna.

Laminated Spruce Logs for First-Class Quality and Longevity

A laminated log is a structural element made by gluing together two or more layers of kiln-dried spruce lamellas under carefully controlled conditions. Each lamella is cut from the densest and strongest part of the spruce trunk, and during assembly, the heartwood side is always turned outward. This orientation ensures dimensional stability and minimizes surface cracking over time.

The result is a beautiful, light-colored wood that is not only visually appealing but also structurally stable and highly suitable for sauna construction.

Laminated logs offer excellent dimensional stability, a naturally elegant appearance, and long-term durability. They are non-toxic, sustainable, and perfectly suited for outdoor saunas exposed to varying weather conditions.

Because of their engineered structure, laminated spruce logs resist warping and cracking, maintaining their form and strength for decades. Spruce resists moisture and wear, ensuring long-term comfort even in demanding conditions.

Beyond performance, laminated logs offer a clean and modern aesthetic that harmonises beautifully with contemporary architecture and outdoor spaces. Each Hetki sauna is crafted from this material, combining natural beauty, technical performance, and a Finnish log-building tradition refined with modern precision.

The Natural Balance of Wood: The Secret Behind the Gentle Heat

The soft, even warmth of a log sauna comes from the natural qualities of wood. Solid timber responds gradually to changes in heat and humidity, helping to keep the sauna air pleasant and balanced throughout the session.

Thick log walls moderate temperature fluctuations and create a natural, gentle warmth that feels soft on the skin and easy to breathe. Unlike lightweight wall structures, solid wood doesn’t heat up suddenly or release heat unevenly – instead, it maintains a calm and comfortable atmosphere.

At the same time, the wood’s breathability and ability to balance humidity keep the air fresh and pleasantly moist. It absorbs excess moisture and releases it back when the air becomes dry – a natural cycle that allows the body to relax and breathing to stay effortless.

This combination – the wood’s natural breathability, its balance of heat and moisture, and the stability of solid construction – creates the signature gentle warmth that defines the authentic and soothing experience of a Hetki sauna.

Hetki’s Signature Craftsmanship: The Dovetail Corner Joints

In a true log sauna, the wall thickness and solid timber structure enable something that lighter constructions simply cannot: the traditional dovetail corner joint.

This classic joinery technique creates an interlocking structure known for its strength, accuracy, and long-term stability. Today, dovetail corner joints are quite rare, as their geometry and production demand advanced machinery, careful alignment, and additional time, making them more complex and costly to produce than simpler corner types.

At Hetki, we keep this heritage alive. Each sauna is built with dovetail joints crafted to fit perfectly with the width and solidity of our spruce logs. Built to last and instantly recognisable for their distinctive look, they represent a blend of traditional craftsmanship and sleek design, perfectly at home even in an urban backyard setting.

A perfect balance of function and form, and a visible sign of true craftsmanship.

The Sauna Experience: Feeling the Difference

The feeling of a log sauna goes beyond technical specifications. The depth and softness of the heat, the way it radiates evenly from the walls, and the calm it creates inside.

The light color, fine grain, and subtle scent of spruce engage all the senses, creating an atmosphere that feels both grounding and uplifting. A wonderful experience for all senses – sight, touch, and smell – enhanced by the natural antibacterial properties of conifer wood, long known for their positive effects on wellbeing.

Every Hetki sauna carries the essence of Finnish forests: calm, balance, and authenticity.

As Alan Jalasjaa, Sauna Ambassador of Sauna From Finland, described it:

“I've learned that not all saunas are the same, and the solid timber frame on my Hetki delivers the deepest, most gentle heat I've ever experienced.”

It’s this unique combination of materials, craftsmanship, and structure that defines the real Finnish sauna experience.

Why a True Log Sauna Matters

The advantages of a solid log structure go beyond technical performance. They shape not only how a sauna works and endures, but also how it feels to experience.

• Stable indoor climate thanks to the thermal mass of wood.

• High durability and structural strength.

• Excellent humidity and acoustic regulation.

• Precise dimensional stability: walls remain tight and true season after season.

• Proven longevity with minimal maintenance.

• Lower operating costs through natural energy efficiency, unlike most outdoor saunas with thinner, non-insulated wall structures.

• And last but not least, that special feeling – the warmth, scent, and calm that engage all senses in a true log sauna.

For users, these qualities mean consistent comfort, reliability, and long-term value.

A log sauna is not a decorative variation of a wooden building. It’s a building type of its own, defined by physics, material science, and cultural heritage.

Every Hetki sauna embodies this principle, built from real Finnish logs not just in appearance but in structure, spirit, and performance.

And when you’re choosing a sauna for your garden, we’re not saying you need to bring out the measuring tape, but it’s worth taking a closer look. Because sometimes, the difference you can see is also the one you’ll feel.