The new Cube Sauna from Finnmark Sauna delivers authentic Finnish wellness in a remarkably compact design. With a footprint of just 145cm × 133cm, this innovative square barrel configuration brings professional-grade sauna bathing to compact gardens, spare rooms, basements, and converted garages, spaces previously considered too small for traditional installations.

Expertly crafted in Estonia with authentic Baltic sauna heritage, each Cube Sauna is backed by our "Sauna from Finland" certification, ensuring every unit meets genuine Finnish construction standards. This revolutionary design maximises interior space whilst maintaining the compact footprint that British homeowners need, whether you're working with a modest city garden or converting a spare room into a wellness sanctuary.

Cube Sauna Options

Our Cube Sauna collection offers four carefully designed variations to suit different spaces and aesthetics, ensuring there's a perfect match for your specific requirements:

Outdoor Cube Sauna Models

• Thermo Wood Cube Outdoor Sauna - Mini (2 Person): Warm honey-brown tones that deepen naturally over time, perfect for traditional garden settings. The organic aesthetic complements existing landscaping beautifully whilst requiring no annual maintenance to preserve its appearance.

• Thermo Wood Cube Outdoor Sauna Black - Mini (2 Person): A contemporary dark aesthetic that creates architectural impact in modern garden designs. The sophisticated deep colour makes a bold statement whilst maintaining the same exceptional weather resistance and thermal performance.

Indoor Cube Sauna Models

• Thermo Wood Cube Indoor Sauna - Mini (2 Person): Sophisticated wood tones that complement contemporary interiors, ideal for spare rooms, basements, and converted garages. The warm timber creates an inviting wellness space that enhances any interior design scheme.

• Thermo Wood Cube Indoor Sauna Black - Mini (2 Person): Dramatic dark timber creating a luxurious spa-like atmosphere. Perfect for homeowners seeking a striking design statement that transforms any room into a high-end personal retreat.

All models feature weather-resistant thermally modified construction with 40mm spruce frames, two-tier aspen benches, and premium 8mm tempered glass. Indoor versions include roof kits for future outdoor relocation, providing valuable flexibility as your circumstances change.

Why Thermally Modified Wood Matters

Thermal modification transforms timber by heating it to 200°C in a controlled environment, permanently altering its cellular structure at a molecular level. This isn't merely a surface treatment; it's a fundamental transformation that delivers exceptional resistance to decay, moisture, and warping without requiring annual treatments or chemical preservatives.

Traditional untreated timber used in outdoor saunas typically needs to be replaced within 5-7 years due to weathering, rot, and structural degradation. It demands yearly applications of oils or protective stains to maintain even basic weather resistance. Thermally modified wood, by contrast, maintains structural integrity for decades with minimal upkeep—simply brush away debris and ensure drainage remains clear.

The naturally darker, richer colour achieved through thermal modification ages beautifully without fading to the dull grey common with untreated timber. For outdoor installations, this means your garden sauna maintains its aesthetic appeal year after year. For indoor installations, the enhanced dimensional stability ensures perfect joinery and seal integrity despite the extreme temperature fluctuations experienced during use, critical for energy efficiency and consistent thermal performance.

Interested in learning more about sauna woods and the importance each variation plays in creating your perfect sauna, we've launched a new guide dedicated to this here.

What's Included

Every complete Cube Sauna package includes:

Core Structure

• 40mm thermally modified spruce frame and staves

• Two-tier thermally modified aspen benches (121cm length, 1-2 person capacity)

• 8mm tempered glass door and front walls

• Thermally modified aspen flooring duckboards

• Integrated ventilation valve

• Bitumen roof shingles with stainless steel frame bands

• Complete assembly hardware and instructions

Heating System

• Narvi NM 6kW authentic Finnish electric heater

• Professional-grade sauna stones for optimal heat distribution

• Rapid heating: typically reaches 70-90°C in 30-45 minutes

Dimensions: L: 145cm | W: 133cm | H: 221cm | Weight: 450kg

Installation Requirements

Outdoor Installation

Outdoor Cube Saunas require a level, stable base measuring a minimum 150cm × 140cm. Suitable foundations include concrete pads, paving slabs, or compacted crushed stone—the key requirement is a solid, level surface free from standing water. The site must offer adequate drainage to prevent water accumulation that could compromise the foundation over time.

Consider positioning carefully for both practical access and visual appeal. Allow sufficient clearance from property boundaries to comply with local planning requirements. Most outdoor installations fall under permitted development rights as the unit measures under 2.5m high, though we recommend verifying requirements with your local planning authority, particularly in conservation areas or properties with restrictive covenants.

Indoor Installation

Space Requirements: Minimum room dimensions 175cm × 165cm (including essential 150mm clearance from walls on all sides). This clearance isn't optional—it ensures proper air circulation and safe heat dissipation. Ceiling height must reach minimum 230cm to accommodate the 221cm sauna height plus necessary clearance above. Floor must support the 450kg unit weight on a level, solid substrate such as concrete, reinforced timber joists, or solid flooring.

Ventilation Requirements: Adequate ventilation proves essential for safe indoor sauna operation—this is a fundamental safety requirement, not an optional feature. The room must provide either natural ventilation through windows or air vents, or mechanical extraction via an extractor fan. Fresh air intake and exhaust are critical for maintaining proper oxygen levels and removing moisture during use. Without proper ventilation, condensation accumulates, potentially causing structural damage, mould growth, and unsafe conditions during sessions.

Electrical Installation: All Cube Sauna models require a dedicated 32-amp circuit installed by a qualified electrician. The 6kW heater must be hardwired directly into your electrical system—standard plug connections cannot safely handle this electrical load. Factor in professional electrical installation costs as a non-negotiable safety consideration in your project budget. Your electrician will install appropriate circuit protection and ensure compliance with current wiring regulations.

Assembly Process: Designed for straightforward DIY assembly over a weekend using basic tools. The modular construction eliminates complex joinery or specialised knowledge. Comprehensive instructions guide you through each step systematically. An assistant proves helpful for positioning larger components due to their weight, though the assembly process itself requires only reasonable DIY experience.

Indoor and Outdoor Versatility

Outdoor Use: Positioned in your garden, the Cube Sauna creates a dedicated wellness sanctuary separate from your main home. This physical separation enhances the psychological benefits—creating a ritual of stepping away from daily concerns into a space dedicated purely to wellbeing. The compact footprint fits comfortably in smaller British gardens where traditional sauna buildings would overwhelm the space.

Year-round outdoor use proves entirely practical with thermally modified construction. British winters present no challenges; indeed, the traditional Finnish practice of moving from intense sauna heat into crisp outdoor air delivers maximum cardiovascular and immune system benefits. Consider positioning near screening plants or fencing for privacy, or site it to capture views across your garden, maximising the connection with nature that enhances the experience.

Indoor Use: Indoor Cube Saunas transform spare rooms, basements, or converted garages into personal spa retreats. The controlled environment eliminates weather considerations, enabling spontaneous sauna sessions regardless of conditions outside. The contemporary aesthetic of thermally modified wood, particularly in black finish, creates a design statement that elevates interior spaces whilst adding genuine value to your property.

Indoor installation offers particular advantages for those with mobility considerations, eliminating the need to navigate gardens in winter weather. The convenience of indoor access often translates to more frequent use, maximising the health benefits of regular sauna bathing. Combined with thoughtful lighting and finishing touches, your indoor Cube Sauna becomes a luxurious retreat that rivals premium spa facilities.

Establishing Your Routine: Traditional Finnish practice recommends 10-15 minute sessions at temperatures between 70-90°C, with cooling periods between rounds. New users should begin conservatively, with shorter sessions at moderate temperatures, gradually building tolerance and discovering personal preferences. Pre-heating typically requires 30-45 minutes, though many modern heater controllers offer programmable timers for scheduled heating.

Post-session care proves minimal. Simply leave the door open to allow moisture to evaporate and air to circulate naturally. The integrated ventilation system facilitates this drying process, preventing condensation issues and maintaining optimal conditions between uses. This simplicity of maintenance allows you to focus on enjoying your wellness routine rather than constant upkeep.

Perfect For

Couples Seeking Private Wellness: The two-person capacity creates an intimate space for couples to share wellness time and build healthy routines together. Regular joint sauna sessions provide opportunities for conversation and connection away from screens and distractions.

Space-Conscious Homeowners: Those with compact gardens or limited interior space now find the Cube Sauna delivers authentic Finnish bathing in remarkably modest dimensions. The 145cm × 133cm footprint represents approximately half the space required by traditional sauna buildings.

First-Time Sauna Buyers: The manageable price point and straightforward installation make the Cube Sauna ideal for those new to sauna ownership. You're receiving genuine "Sauna from Finland" certified quality without committing to expensive permanent structures.

Regular Wellness Enthusiasts: Consistent sauna practice delivers the greatest health benefits. Home ownership, eliminating travel to spas or gyms, translates to regular use that builds genuine wellness improvements. Your Cube Sauna remains available 24/7 without membership fees.

Property Developers and Landlords: Cube Saunas add genuine luxury amenities that differentiate properties in competitive markets. The straightforward installation and modest space requirements make this practical even in urban developments.

Why Choose Finnmark Sauna?

Operating from Durham with a dedicated team of 40 sauna specialists, Finnmark Sauna is the UK's first "Sauna from Finland" member, meeting rigorous standards that define genuine Finnish construction. This certification isn't marketing; it's verification, ensuring construction methods, materials, and thermal performance meet authentic Finnish standards.

We stock exclusively premium brands, including HUUM, Narvi, Tulikivi, IKI and Kastor,  never compromising quality to hit price points. This uncompromising approach has built our reputation across the UK's sauna community.

Our Estonian manufacturing partners bring generations of Baltic sauna heritage to every unit. This isn't mass-produced furniture—it's crafted by specialists who understand authentic sauna construction demands specific knowledge, materials, and techniques. Proper air circulation, thermal insulation, and precise construction tolerances all impact experience quality—technical requirements that generic manufacturers often misunderstand or compromise.

When you invest in a Finnmark Cube Sauna, you're acquiring authentic Finnish wellness culture, thoughtfully adapted for British homes and gardens.

Frequently Asked Questions

How long does the Cube Sauna take to heat up?

The Narvi NM 6kW heater typically reaches optimal temperature (70-90°C) within 30-45 minutes from ambient temperature. In the summer months, with moderate temperatures, heat faster, whilst in winter or higher temperature preferences may extend to 45 minutes. Many heater controllers offer programmable timers for scheduled pre-heating.

Can I install the Cube Sauna myself?

Yes, the modular design suits DIY assembly over a weekend with basic tools and reasonable DIY experience. An assistant helps with heavier components. However, electrical connection absolutely requires a qualified electrician—the 6kW heater demands a dedicated 32-amp circuit that cannot use standard socket connections.

What maintenance does thermally modified wood require?

Minimal maintenance—one of the Cube Sauna's greatest advantages. Thermally modified wood resists decay, moisture, and UV damage without annual treatments. Simply brush away exterior debris, ensure drainage remains clear, and gently clean interior surfaces post-session. The natural darkening over time enhances appearance rather than detracting from it.

Can the indoor model be moved outdoors later?

Yes, indoor models include roof kits for this flexibility. Whilst optimised for indoor use, the thermally modified wood construction can relocate outdoors if circumstances change. However, reassembly involves significant effort, and outdoor exposure gradually alters appearance. Choose the correct installation type initially when possible.

Do I need planning permission for an outdoor Cube Sauna?

Most outdoor installations fall under permitted development rights as the unit measures under 2.5m high. However, conservation areas, Areas of Outstanding Natural Beauty, or restrictive covenants may face additional restrictions. Verify requirements with your local planning authority before purchasing—a brief inquiry prevents potential complications.

How many people can use the Cube Sauna comfortably?

Official capacity is two adults in a traditional Finnish arrangement. The 121cm bench length allows two people to sit upright on the lower bench, or one to recline whilst another sits on the upper tier. Ideal for couples seeking shared wellness time. Solo users can recline fully or alternate positions comfortably. Attempting to fit three people compromises comfort and an authentic sauna experience.