composite / Natural Fibre Composite / Cementitious Composite
Hempcrete Blocks/Panels (150mm, 200mm, 250mm, 300mm)
Hempcrete blocks are lightweight lime?hemp composites (typical density ~256?352 kg/m?) with low compressive strength (~0.11?0.47 MPa), suited to non-structural infill and insulation.
Atlas code
COM-NFC-CC-001
At-a-glance signals
Hempcrete blocks are lightweight lime?hemp composites (typical density ~256?352 kg/m?) with low compressive strength (~0.11?0.47 MPa), suited to non-structural infill and insulation.
Overview
Executive summary
Hempcrete blocks are non-structural bio-composite masonry units made from hemp hurd and lime-based binders. Literature reports hempcrete densities around 300?350 kg/m?, with compressive strength typically 0.11?0.47 MPa depending on mix design. Practitioner guidance notes wall mixes around 16?22 lb/ft? (?256?352 kg/m?). These values confirm hempcrete?s role as an insulating infill rather than a load-bearing material.
Best when…
- Carbon negative material (sequesters CO2)
- Excellent thermal insulation and mass combination
- Superior moisture buffering capacity
- Fire resistant (BAL-FZ rated with render)
- Non-toxic with zero VOC emissions
- Pest and mould resistant
- Lightweight (reduces foundation requirements)
- 100% recyclable and biodegradable
- Self-healing micro-cracks through carbonation
- Good acoustic absorption
Top advantages
- 01 Carbon negative material (sequesters CO2)
- 02 Excellent thermal insulation and mass combination
- 03 Superior moisture buffering capacity
- 04 Fire resistant (BAL-FZ rated with render)
- 05 Non-toxic with zero VOC emissions
Top limitations
- 01 Low structural strength (requires load-bearing frame)
- 02 Longer drying time (4-6 weeks before rendering)
- 03 Limited Australian manufacturers
- 04 Higher initial cost than conventional masonry
- 05 Requires specialist installation knowledge
Technical
Physical ·9
- Density
- 16?22 lb/ft? (?256?352 kg/m?); literature reports ~300?350 kg/m? kg/m³
- Specific gravity
- 0.25-0.40
- Porosity
- 71-84 %
- Water absorption
- 300-400 %
- Hardness
- Soft
- UV resistance
- Good // Protected by lime binder
- Chemical resistance
- Alkaline resistant // pH ~12 environment
- pH tolerance
- 11-13
- Surface roughness
- 5-10 µm
Mechanical ·7
- Tensile strength
- 0.01-0.035 MPa
- Compressive strength
- 0.11?0.47 MPa (reported range in hempcrete studies) MPa
- Flexural strength
- 0.05-0.10 MPa
- Shear strength
- 0.05-0.15 MPa
- Poisson's ratio
- 0.15-0.20
- Impact resistance
- Low // Soft material
- Creep resistance
- Moderate // Some deformation under load
Sustainability & Health
Embodied carbon & energy ·7
- Embodied carbon
- -16 to -135 // kg CO2e/m³
- Carbon footprint
- -0.3 to -1.0 // kg CO2/kg material
- Embodied energy
- 30-50 MJ/kg // MJ/m³ - Very low
- Water footprint
- 200-400 L/kg // L/m³ - Hemp cultivation
- Recycled content
- 0 % // Natural materials
- Renewable content
- 84 % // % hemp content
- Circular score
- 9/10 // Excellent circularity
Compliance & Fire
Fire performance ·6
- Combustibility class
- Non-combustible // With lime render
- Fire resistance level
- 60 // minutes - 1 hour rating
- Ignition temp
- >300 °C // °C - Hemp protected by lime
- Flame spread index
- <25
- Smoke dev. index
- <50
- Heat release rate
- Very low // Minimal heat release
Cost & Lifecycle
Capex & lead time ·6
- Material cost (range)
- $109-330 // AUD per m²
- Material cost (per unit)
- $15-45 // AUD per block depending on size
- Lead time
- 2-6 // weeks depending on quantity
- Lifecycle cost
- $400-600 // AUD per m² over 50 years
- Annual maintenance
- $0-5 // AUD per m² - Minimal
- Market availability
- Limited // Growing but limited suppliers
Service life & durability ·3
- Expected lifespan
- 50-100+ // years - centuries possible
- Maintenance interval
- 10-15 // years for render refresh
- Warranty period
- 10-25 // years manufacturer warranty
Layer D
Where it's used
Non-structural wall infill systems
Thermal insulation for walls
Acoustic insulation panels
Retrofit insulation over existing frames
Fire-resistant wall assemblies
Passive house construction
Heritage building restoration
Bushfire-prone area construction