Sustainability in Bali is not a design aesthetic. It's survival.

A sustainable built home is only one part of the equation. It relies entirely on the ecosystem dimension you are part of—ideally natural pools, permaculture-first principle, forest-first environments, living-water priority, and above all, community-first living. In this dimension, the very idea, for example, of using chemical fogging becomes unthinkable.

This article focuses on materials—the tangible decisions that determine whether your building becomes part of the solution or part of the problem. But remember: even the most sustainable materials fail without the ecosystem they sit in.

The island's relentless 32–35°C heat, 80–95% humidity, subterranean termites, monsoon deluges, and regular seismic tremors destroy imported "eco-friendly" materials in under five years. What works in Scandinavia, California, or even Java often becomes expensive compost here.

This isn't theory—it's thermodynamics, entomology, and supply-chain physics.

The Two Laws That Rule Everything

When building in Bali, sustainability collapses into two brutal metrics:

1. Embedded Energy
How much pollution was created to make and transport this material? That Italian marble might be gorgeous, but it arrived on a container ship burning bunker fuel—emitting more CO₂ than your entire building will save in a decade.

2. Bioclimatic Fit
Can your building stay at 26–28°C indoors without running AC 24/7? A concrete-batako villa in Canggu can hit 38°C indoors by 2 PM, forcing AC bills of 3–5 million rupiah monthly. A well-designed bamboo structure with proper ventilation? 26°C naturally, zero electricity. If your walls turn your bedroom into an oven, you've failed—regardless of how "green" the brochure claimed it was.

Projects like Green School and Green Village (built almost entirely from treated bamboo by IBUKU since 2007) prove that tropical architecture can be luxurious, seismically safe, and near-zero-carbon when you respect these principles.

Sustainable Materials: Use These Without Hesitation

1. Properly Treated Bamboo (The Undisputed Champion)

Bamboo grows 20–90 cm per day, sequesters more CO₂ than any tree, has tensile strength exceeding steel, and bends instead of breaking during earthquakes. It's the closest thing Bali has to "native structural steel."

The catch? Treatment is everything. Untreated or poorly treated bamboo becomes powder within 18–36 months thanks to powder-post beetles.

Critical requirement: Demand immersion treatment with borax + boron solution (non-toxic). Insist on Bamboo U or IBUKU-level protocols. When done right, bamboo structures last 30–50+ years.

Species to use: Giant bamboo varieties like Petung (Dendrocalamus asper), Tali, or Hitam.

2. Natural Stones (Breathable and Eternal)

Black Lava Stone / Andesite
Mold-resistant, zero maintenance, naturally breathable, ages like fine wine. Creates a thermal "skin" that regulates interior humidity.

River Stone
Perfect for foundations—eliminates 70–90% of concrete needs. Just ensure ethical sourcing that doesn't disrupt sawah(rice field) irrigation systems.

Ancient Coral Stone
Quarried from raised fossil reefs in Bukit and Nusa Penida (not live coral). Extraordinarily durable with natural insulation properties.

Non-negotiable: Verify stones come from legal quarries with proper environmental permits.

3. Cob / Adobe (The True Low-Cement Earth Option)

Why cob outperforms rammed earth in Bali:

Cob uses minimal or zero cement—typically just clay, sand, straw, and water mixed on-site. The Bukit peninsula and northern Bali have near-perfect limestone-clay soils for cob construction.

The thermodynamic reality in Bali's tropics:

Unlike temperate climates where thermal mass works by absorbing daytime heat and releasing it at night, Bali's cob walls function differently. The earth acts as a perpetual heat sink—the constant contact with the ground allows heat to continuously dissipate downward into the cooler earth mass below, rather than cycling back into the interior at night.

Build walls 400–600mm thick and the result: bedrooms stay at 24–27°C without AC, even during peak heat.

Embodied carbon? Near-zero when produced on-site with minimal cement.

Critical distinction from rammed earth:

Rammed earth typically uses 5–8% cement as a stabilizer. While this is lower concentration than batako's ~10% cement content, the math reveals a problem:

• A 5m × 3m batako wall (90mm thick) = 1.35 m³ volume

• The same 5m × 3m rammed earth wall (500mm thick) = 7.5 m³ volume

• That's 5.5 times more material

Result: A rammed earth house can use 2.75 times more total cement than a batako house despite lower cement percentage.

Cob avoids this entirely by using little to no cement, relying instead on proper curing, wall thickness, and clay-straw binding for structural integrity.

4. Reclaimed Ulin (Ironwood), Reclaimed Teak, or Coconut Timber

Reclaimed Ulin is practically immortal—old wharf piles routinely last 80–100 years submerged in salt water. It's naturally termite-resistant and harder than most tropical hardwoods.

The golden rule: Only use reclaimed wood. Freshly cut Ulin or Merbau drives deforestation in Kalimantan and Sumatra.

The emerging star: Coconut timber from senile palms (70+ years old). Surprisingly hard, Class I durability, naturally termite-resistant, abundant, and beautiful dark grain. Using it prevents burning of old palms and creates zero new deforestation.

5. Alang-Alang Natural Thatch (Best Passive Cooling Roof in the Tropics)

A 300–400mm thick alang-alang (Imperata cylindrica) roof keeps attic temperatures 8–12°C cooler than metal or tile. The grass weave allows hot air to escape naturally—something synthetic materials cannot replicate.

Lifespan: 7–12 years with proper pitch (minimum 45°), generous overhangs, and occasional grooming.

End of life: Becomes garden mulch. Zero landfill.

Note: Synthetic thatch cannot compete thermodynamically or ecologically—it traps heat, sheds microplastics, and off-gasses VOCs.

6. Village-Fired Red Brick (Bata Merah)

Produced in thousands of small kilns across Java and Bali using rice-husk or coconut-shell fuel—drastically lower emissions than industrial cement production.

Why it works: Porous structure breathes and regulates humidity naturally. Pair with lime plaster (not cement render) for maximum breathability. Cheap, durable, and looks better with age.

Strong Supporting Materials (Increasingly Available in 2025)

• Coconut Wood & Husk Panels – Zero-waste, abundant, beautiful grain

• AAC Blocks with Volcanic Ash Mix – If concrete is unavoidable, these are the only acceptable alternative

• Hempcrete or Mycelium Panels – Carbon-negative, astonishing insulation (already used in several Ubud/Bukit projects)

• Recycled Ocean Plastic Bricks – Good for non-structural walls when local earth isn't suitable

Materials to Avoid (Or Your Building Will Punish You)

❌ Standard Concrete Batako

Why people use it: Cheap, available everywhere, familiar to local builders.

Why it fails: Cement production accounts for 8% of global CO₂ emissions. Hollow concrete blocks (batako) have almost zero insulation—your building becomes an oven, forcing permanent AC dependency.

The result: High operational carbon for decades.

Use instead: Cob for walls, AAC blocks with volcanic ash mix if concrete is unavoidable, river stone for foundations.

Acceptable use: Foundations below damp-proof course only.

❌ Uncertified Tropical Timber

Why people use it: Cheap availability, beautiful hardwood aesthetics.

Why it fails: Cheap "new" Merbau, Bangkirai, or Teak flooding the market in 2025 is still directly linked to illegal Kalimantan deforestation.

Always demand: SVLK + FLEGT certification. No paperwork? Walk away.

Use instead: Reclaimed timber or coconut wood.

❌ Floor-to-Ceiling Glass Curtain Walls

Why people use it: Modern aesthetics, views, Instagram appeal.

Why it fails: The fastest way to make a building uninhabitable without 24/7 air conditioning. Even with double Low-E glass, solar heat gain in the tropics is catastrophic. Glass facades act as greenhouses, trapping massive amounts of heat and creating energy slaves.

If glass is non-negotiable: Use only on north/east façades with 2m+ overhangs and external shading systems.

❌ Asbestos Cement Roofing ("Asbes")

Why people use it: Dirt cheap, lightweight, widely available.

Why it fails: Still legally sold in Indonesia as of 2025. Carcinogenic, friable, impossible to dispose of safely.

There is zero excuse for using this material.

❌ Synthetic / PVC "Alang-Alang"

Why people use it: Lasts 20 years, no maintenance, fire-resistant.

Why it fails: Sheds microplastics into waterways, traps heat (zero ventilation), and off-gasses volatile organic compounds. Defeats the entire purpose of tropical passive cooling design.

❌ Polystyrene (Styrofoam) Insulation

Why people use it: Cheap insulation, easy to install.

Why it fails: Blocks breathability, becomes termite buffet when exposed, and pollutes waterways when fragments blow away during construction. Bali's open construction sites routinely send foam particles into rice fields and rivers.

⚠️ Paras (Soft White Limestone)

Why people use it: Beautiful for carvings, traditional aesthetics, easy to carve.

Why it's problematic: Large-scale structural use is environmentally disastrous. Quarries in Mengwi and Tabanan have left moonscapes and caused deadly landslides.

Acceptable use: Sparingly and only from licensed, rehabilitated quarries. Beautiful for temple carvings and decorative cladding, but not for large-scale structural use.

Why Good Materials Fail: The Design Integration Checklist

Here's the uncomfortable truth: You see $500,000 bamboo villas become moldy disasters within 18 months. Not because bamboo failed—because the design ignored these non-negotiables:

1. Termite Strategy

Nothing untreated lasts. Period. Bali's subterranean termites destroy softwoods and untreated bamboo in under three years. Only treated bamboo, Ulin, coconut timber, and stone provide stable foundations.

2. Ventilation Design

A "sustainable" material in a sealed box still molds. Cross-ventilation + elevated floors + high ceilings are mandatory in Bali's humidity.

3. Overhangs & Orientation

1.5–2.5m eaves reduce solar gain by 70%. Deep overhangs are not decorative—they're load-bearing climate control.

4. Passive Cooling Hierarchy

Prioritize in this order:
Roof insulation > wall thermal mass > shading > ventilation > (only then) fans/AC

5. Seismic Design

Light, flexible, redundant systems (bamboo, timber frames, light cladding) survive earthquakes. Brittle heavy masonry does not.

6. Circularity

Bali has no industrial recycling infrastructure. Choose materials that rot cleanly, burn safely, or can be reused indefinitely without processing.

Projects That Work

• Green School / Green Village (IBUKU) – 100% bamboo campus, zero AC in classrooms, operating since 2007

• Eco Village Sibang & Ubud – Built with cob, reclaimed wood, bamboo, and alang-alang; many open villas showcasing natural materials and tropical design

• The Slow Canggu – Rammed earth + reclaimed timber + alang-alang

• Bawa House (Stilt Studios) – Prefab coconut wood + elevated design

These aren't experimental prototypes. They're lived-in proof that sustainable tropical architecture performs better than conventional concrete boxes.

The Economics Nobody Tells You

"Sustainable building costs more" is the industry's favorite myth.

Reality: A properly designed bamboo or cob house costs 15–30% less per year to operate than a concrete-glass box. Factor in 15-year operating costs (AC bills, maintenance, replacements) and sustainability becomes the financially sensible choice.

The wrong materials turn your dream home into a hot, moldy, money-burning liability that loses value.

The right ones create an heirloom that improves the island and appreciates over decades.

Final Word: Materials Are Just One Part of the System

Sustainable construction in Bali isn't just about the materials.

Materials are one critical piece—but remember: a bamboo house with a chlorinated pool, no forest layers, and zero community integration is just a beautiful box that misses the ecosystem point.

Real sustainability is systems thinking:

The Materials Foundation:

• Low embedded energy materials

• Passive cooling architecture

• Breathable, humidity-regulating materials

• Ecological alignment with tropical conditions

• Respect for seismic reality

Plus The Ecosystem Integration:

• Natural pools and water systems

• Permaculture-first principle

• Forest-first environments

• Community integration and mutual support

Buildings and land that honor these principles perform better, last longer, cost less to operate, and actively protect Bali's fragile ecosystems.

Buildings that ignore them become expensive problems within five years.

The materials are where you start. The ecosystem is where you finish.

Ready to Build a Sustainable Home in Bali?

For authentic cob and natural building expertise in Bali, contact Kurt Beckman, who specializes in sustainable cob construction using Bali's ideal limestone-clay soils, with a focus on natural cooling and dehumidifying—creating homes that breathe with the climate rather than fight against it.

WhatsApp: +62 813-3898-0291

Related Reading

Feel the Water
Airconditioner
Trust the Nymph
Smell the Soil

Key Resources & Citations

• Green Village Bali & IBUKU – Bamboo architecture portfolio (2007–2025)

• Bamboo U – Treatment protocols and construction training

• Pablo Luna Studio – Alang-alang technical specifications

• Bali Best Build – Local materials review 2025

• IBUKU / Green School case studies – Long-term performance data

• Kurt Beckman field data – Cob thermal performance and alang-alang cooling effects in Bali's tropical context

Last updated: November 2025