What are Sustainable Materials?
Sustainable materials are building products chosen to minimize environmental impact across their life cycle — from extraction and manufacturing to use and disposal. Architects weigh embodied carbon, renewability, durability, and recyclability when specifying them.
Sustainable materials are construction materials with low embodied carbon, renewable or recycled content, and long service life — such as timber, bamboo, rammed earth, and recycled steel — chosen to reduce a building's total environmental footprint.
Try it: interactive calculator
Step-by-step worked examples
A project uses 5,000 kg of concrete with an emission factor of 0.13 kgCO2e/kg. Find the embodied carbon.
EC = m × f EC = 5000 × 0.13 EC = 650 kgCO2e
The same project could switch to cross-laminated timber (CLT) at 0.06 kgCO2e/kg for an equivalent 3,000 kg. Compare embodied carbon.
EC(CLT) = 3000 × 0.06 = 180 kgCO2e EC(concrete) = 650 kgCO2e (from Example 1) Savings = 650 − 180 = 470 kgCO2e (≈72% reduction)
Recycled steel (0.45 kgCO2e/kg) replaces virgin steel (1.85 kgCO2e/kg) for a 2,000 kg structural frame. What is the carbon saved?
EC(virgin) = 2000 × 1.85 = 3700 kgCO2e EC(recycled) = 2000 × 0.45 = 900 kgCO2e Savings = 3700 − 900 = 2800 kgCO2e (≈76% reduction)
Flashcards
Quick quiz
Q1.Embodied carbon includes emissions from…
Q2.Which material typically has the LOWEST embodied carbon per kg?
Q3.5,000 kg of a material with factor 0.10 kgCO2e/kg has embodied carbon of…
Q4.Choosing recycled steel over virgin steel primarily reduces…
The full card deck, worked steps and AI-tutor support for “What are Sustainable Materials?” are in Notek — study by hand before your exam.
Common mistakes
Sustainable materials are always more expensive. — Correct: Many, like rammed earth or reclaimed materials, can be cost-competitive or cheaper depending on local availability.
Natural materials are automatically low-carbon. — Correct: Processing and transport matter too — a locally sourced but heavily processed material may still have high embodied carbon.
Embodied carbon only matters for large commercial buildings. — Correct: It matters for any project; residential renovations and small buildings also benefit from material choice.
Recyclable and recycled mean the same thing. — Correct: 'Recycled' means the material already contains reused content; 'recyclable' means it CAN be recycled at end of life — not the same impact today.
FAQ
What are sustainable materials?
Building materials chosen for low environmental impact across their life cycle — low embodied carbon, renewable or recycled content, and durability.
What is the formula for embodied carbon of a material?
EC = m × f, where m is the material quantity (kg) and f is its emission factor (kgCO2e/kg).
What are examples of sustainable materials?
Timber/CLT, bamboo, rammed earth, recycled steel, reclaimed brick, and low-carbon concrete are common examples.
How do you calculate the embodied carbon of a building material?
Multiply the material's quantity (mass) by its emission factor from a verified environmental product declaration (EPD) or database.