Custom Sauna Design: What to Consider Before You Build

Building for rhythm, not trend

A custom sauna is not a product to purchase but a structure to shape and live with. To design one well is to think about rhythm, light, and heat long before the first log is cut. It is about creating a space that feels inevitable, built to last, not to impress.

The best saunas are not complex. They are calm, precise, and deeply connected to their setting. Yet behind that simplicity lies a series of considered decisions. Every choice, from timber to stove placement, influences how the sauna will perform and how it will feel.

This is a guide to those decisions: what to think about before you build, and how to design a sauna that belongs to both you and its place.

Begin with purpose

Before size, shape, or materials, begin with how the sauna will be used. A private retreat at home has a different rhythm from one shared with guests at a lodge. A daily sauna after work calls for ease and intimacy, while a destination sauna on a remote property might prioritise view and atmosphere.

Ask simple questions. How often will it be used? By how many people? What kind of heat do you prefer: dry, gentle, or intense? Will it be paired with water, a cold shower, or open sea?

These answers define everything that follows. A sauna built for personal ritual should feel enclosed and still, while a social sauna benefits from generous benches and a stronger connection to the outside.

Purpose determines design.

The importance of place

Every great sauna belongs to its setting. In New Zealand, that means reading the landscape carefully.

A sauna built by the ocean must respond to salt air and shifting light. One in alpine snow needs to hold heat and endure frost. In the bush, the building should sit quietly within the trees, visible only through glimpses of smoke and steam.

When choosing location, consider three things: orientation, access, and shelter. The entry should feel natural to reach, even barefoot and wet. The structure should face a view worth watching as the body cools. And it should sit where wind and weather can be felt but not fought.

A sauna that belongs to its landscape always feels calm. It does not try to dominate the view, only to frame it.

Material honesty

A sauna is one of the few buildings where you feel every surface directly. For that reason, material choice defines experience.

Solid New Zealand Redwood is the foundation of every Heritage sauna. Locally grown and milled, it is a timber that endures humidity and heat without distortion. It holds warmth naturally, releasing it slowly and evenly. Over years, its colour deepens and its scent remains.

Unlike lined or panelled construction, log-built saunas are made from the timber itself. Each log is both the interior and exterior wall, connected through dovetail joins that settle and strengthen with time.

This honesty gives the building its permanence. There are no hidden layers, no insulation to replace, no cladding to maintain. What you see is what holds it together.

When planning a custom sauna, start with the material. Choose what will age well, not just what looks new.

The heart of heat

The stove is the heart of the sauna. It dictates how warmth builds, spreads, and sustains.

There are two main options: wood-fired or electric. Each has its rhythm.

A wood-fired stove offers the truest form of ritual. Lighting the fire becomes part of the experience: stacking wood, tending flame, waiting for the heat to rise. The sound and scent of burning timber bring a kind of calm that no machine can replicate.

An electric stove, by contrast, offers precision. It heats consistently and can be controlled easily. For urban homes or lodges where simplicity matters, it is practical and refined.

Both can be beautiful. What matters is proportion. The stove should match the size of the room and sit as a natural focal point, balanced by benches and air flow.

When designing your sauna, think about how you want to build heat. Some prefer slow warmth that lingers, others a sharp rise followed by cool immersion. The right stove, placed correctly, will define that rhythm.

Space and proportion

A custom sauna should never feel oversized or underused. Good proportion makes it comfortable, efficient, and quiet.

For two to three people, an interior of around four to five square metres is generous. For a lodge or retreat with multiple guests, six to eight square metres allows for layered benches and movement.

Height matters. Too low, and the heat feels uneven. Too high, and the air becomes difficult to balance. A ceiling between 2.1 and 2.3 metres keeps warmth where it is needed while maintaining a sense of space.

Benches should allow for sitting and reclining. Upper benches are warmer, lower benches cooler. A custom design can include both, giving users control over intensity.

The key is not size but proportion. The sauna should feel full when used and calm when empty.

Light, air, and orientation

Light in a sauna should be soft, not bright. Natural light connects the user to time and place, while shadows preserve calm. Small windows can frame a view of sky, water, or trees without sacrificing privacy or insulation.

Artificial lighting works best when indirect, hidden beneath benches or behind timber slats. The glow should feel like firelight, never harsh.

Ventilation is essential. Fresh air enters low and exits high, creating gentle circulation. A well-ventilated sauna feels alive, with air that moves and breathes.

Together, light and air turn heat into experience. They make the sauna feel like part of its surroundings rather than separate from it.

Integrating the cool

A sauna is never only about heat. The transition to cold is what completes the ritual.

In Scandinavian tradition, users step directly into snow, lake, or sea. In New Zealand, the options vary by site. A plunge pool, outdoor shower, or simple bucket of cold water achieves the same renewal.

When designing your sauna, consider how that transition will happen. A clear path to water or fresh air makes the experience seamless. Even a small deck or outdoor bench can transform how the space is used.

Cool air after heat brings balance. Designing for that moment is as important as the sauna itself.

Building for permanence

The most meaningful structures are those that remain. In an age of fast design and temporary materials, permanence has become a form of luxury.

A well-built log sauna will outlast its owner. The timber settles, seasons, and strengthens. The roof, often finished in Coloursteel, endures coastal wind and alpine snow alike. The joints tighten rather than loosen.

When you commission a sauna, think of it as an heirloom. It should be something that future generations can still use, repair, and enjoy. This philosophy of building once, and building well, defines Heritage craft.

Permanence is not only practical. It is emotional. A structure that lasts becomes part of your story.

Sustainability through design

Sustainability is often measured in short cycles: energy use, transport, or recyclability. True sustainability comes from longevity.

Each Heritage sauna is built from renewable materials sourced in New Zealand. Redwood grows well in local climates and is harvested responsibly. Its durability means less need for treatment or replacement.

Because the structure is solid timber, there are no hidden layers to degrade. Maintenance is minimal, repair simple.

When designing a custom sauna, the most sustainable choice is to design for permanence. Build once, use for decades, and let materials age naturally.

Working with your surroundings

A sauna is not an object to place but a structure to integrate. The best designs respond to slope, vegetation, and view.

On uneven terrain, a sauna can sit partially recessed, anchored to rock or soil. In open fields, it can align with existing lines in the landscape, a fence, a tree, or the horizon. In coastal sites, it should face the water while shielding from wind.

Think about the approach. The path to the door is part of the experience. Walking barefoot over timber or gravel, feeling the temperature change, prepares the mind for what comes next.

Even small design gestures, like orienting the door away from the prevailing wind or framing a single view, can transform a sauna from structure to sanctuary.

Collaboration and craft

For homeowners working with architects or designers, collaboration is essential. A sauna can be built as an extension of the home’s material language or as a distinct standalone retreat.

Architects bring precision in siting and proportion. Builders bring an understanding of timber, heat, and craft. Together, they create balance between design and function.

A custom sauna should never feel like an addition. It should feel as if it was always meant to be there.

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Designing a custom sauna is not about following a plan but about creating a rhythm that suits your life and landscape. It is an act of craft, of care, and of patience.

Before you build, consider how it will be used, where it will sit, and how it will last. Choose materials that age well. Think about light, air, and access to cold.

When done well, a sauna becomes more than a room of heat. It becomes a place of permanence, something that restores, season after season.

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