Contents

1. Is building a DIY sauna right for you?
2. Do you need a building consent in NZ?
3. Where to build your sauna – Indoor or Outdoor?
4. Essential materials & Components checklist
5. Understanding heat, ventilation & safety
6. Why proper ventilation is non-negotiable
7. Choosing the right heater & electrical setup
8. Timber selection: Why we recommend SAWO
9. Avoiding the most common DIY mistakes
10. Why use a Sauna People DIY Kit?
11. Final advice from Warren

1. Is building a DIY sauna right for you?

If you’re a confident DIYer with solid tools, patience, and attention to detail – yes. But don’t underestimate the complexity. A sauna is more than a timber box with a heater. It involves heat/air convection, vapour control, and fire safety – and getting it wrong can be expensive or dangerous.

2. Do you need a building consent in NZ?

Indoor saunas are usually exempt from building consent under Schedule 1 of the NZ Building Act, as long as they are:

• Are built inside an existing structure
• Do not alter load-bearing walls
• Do not involve significant plumbing

Outdoor saunas may require consent if:

• They’re larger than 10m2
• They include plumbing, drainage, or mains electricity
• They’re closer than 1 metre to a boundary

Always check with your local council before starting, especially if you’re adding external electrical work or plumbing.

3. Where to build your sauna – Indoor or Outdoor?

The choice between an indoor or outdoor sauna depends on space, climate, budget, and the type of experience you want. Indoor saunas offer convenience and year-round use, while outdoor saunas provide a more natural, authentic feel with greater design flexibility.

Indoor Saunas

• Pros: Convenient access, usable year-round, can be integrated into existing spaces (like a bathroom or basement), and often lower upfront cost.
• Cons: Limited size and design options, may need ventilation upgrades or minor structural work, and can feel less connected to nature.
• Best for: Those who value convenience and prefer a compact, low-maintenance solution.

Outdoor Saunas

• Pros: Stronger connection to nature, flexible designs (barrel, pod, cabin), immersive atmosphere, and ideal if near a body of water.
• Cons: Requires more space, higher upfront costs for construction and electrical setup, and greater maintenance to handle weather.
• Best for: Those with space to spare who want a traditional, immersive sauna experience and don’t mind extra upkeep.

4. Essential Materials & components checklist

Every proper sauna build will require:

• A SAWO Sauna Heater (Electric or Wood burning)
• Barrier paper silver foil insulation (reflective + vapour control)
• Kiln-dried timber cladding & benches
• Stones (for steam and heat retention)
• Safety rails, vent grilles, LED lighting
• Tempered glass for window or door
• Non-corrosive fasteners & aluminum tape
• Wall cavity battens + ventilation clearance

Optional extras: Thermometers, hygrometers, WIFI controllers.

5. Understanding heat, ventilation & safety

A Sauna is a room that relies on heat/air convection:

• An intake vent down low and/or near the heater is required to ‘feed’ the convection heater.
• An exhaust vent (higher on the opposite wall or in the ceiling) will enable an outlet ‘convection loop’.

This creates an airflow loop, allowing fresh air to circulate and moist air to exit. A poorly ventilated sauna feels stuffy, fails to heat properly, and can lead to timber rot or mould.

6. Why proper heat and vapour barrier is non-negotiable

We bundle our sauna barrier paper with our heaters for good reason:

• Reflects radiant heat back into the sauna
• Acts as a vapour barrier, stopping steam damage
• Ensures faster heat-up times and better efficiency
• Prevents moisture damage to framing and plasterboard

Every seam should be taped and sealed.

7. Choosing the right heater & electrical setup

We use only SAWO heaters rated for the volume of your sauna (e.g. a 4.5kW unit for ~5m3 space). Oversizing doesn’t help; it just wastes energy and increases the chance of damaging sauna timber.

• All wiring must be installed by a licensed NZ electrician.
• Heaters must be mounted at manufacturer- recommended heights and with required safety clearances.
• Include a timer, controller, or safety cut-off.
• We can provide sauna wiring for as an optional extra with our DIY kits.

8. Timber selection: Why we recommend SAWO

Timber choice impacts performance, safety, and lifespan. The best sauna woods are Arctic Circle grown timbers like Western Red Cedar, Aspen, and Spruce – especially from Arctic regions. They insulate heat well, handle rapid temperature changes, and stay cool to the touch for comfortable seating.

• Cedar: Warm reddish tone, durable outdoors, natural aroma repels insects and mould.
• Aspen: Pale, knot-free, highly resistant to bacteria and fungi, ideal for public saunas.
• Spruce: Light yellow, durable, with a calming forest-like scent.

SAWO timber goes further: it’s kiln-dried, resin-free, sustainably sourced from Nordic forests, and specifically rated for sauna use.

Our sauna timbers are engineered for sauna use: Our Tongue and Grove (T&G) profiles are optimised for sauna use with Long tongue/tails and drip lines. Locally available T&G profiles risk opening up over time and exposing the silver barrier paper behind.

Cheaper timbers may warp, crack, or release sap under heat, leading to costly repairs and safety risks. Investing in sauna-grade timber ensures beauty, durability, and a safe experience.

9. Avoiding the Most Common DIY Sauna Mistakes

Timber isn’t just cosmetic – it affects performance, safety, and lifespan. SAWO sauna timber is:

• Kiln-dried to handle heat and moisture, and avoid resin leakage.
• Sourced from sustainable, slow-grown Nordic forests
• Rated for sauna-specific use

Cheaper timber might seem appealing at first glance, but it warps, cracks, or emits sap when exposed to high heat. That means costly repairs conditions, and potentially unsafe.

10. Why use a Sauna People DIY kit?

Our DIY kits are curated to give you everything you need, nothing you don’t:

• SAWO heater matched to space volume
• Silver barrier foil backed paper to enclose heat and vapour in your sauna. Our barrier paper is fiberglass reinforced, and does not use rubber or plastics.
• Accessories, vents, lights, fasteners (screws) can be included
• Designed for NZ standards, climate, and building code

Explore Our DIY Sauna Kits.

11. Final advice from Warren

“We leverage more than 30 years of experience installing saunas and steam rooms, and worked with many contract builders too, so we know a thing or two about the common challenges with sauna builds. We also know first-hand that building your own sauna is one of the most satisfying projects you can take on, but it’s not one to rush or wing! If you’re going to do it, do it right first time, and don’t cut corners”

His advice?

• Use materials built for the job it will make a massive difference to the aesthetics of your sauna over time
• Respect the heat, moisture, and electrical risks
• Don’t skip the barrier and insulation (ever)
• Take your time, your body (and your sauna) will thank you
• Feel free to ask questions along the way. We’re here to help.

If you’d like support selecting the right kit, or just need a second opinion on your plan – get in touch with our team.

We’re Sauna People, after all.