Block · Sizes pending
Stone — indicative fig. M·118
Fire A1 A1 Non-combustibleEmbodied carbon 0.01kgCO₂e/kg LowCompressive 50-200MPa StructuralDesign life 75yr Durable
Natural slate stone for roofing tiles and exterior cladding with excellent weather resistance
01 Physical
Density 2650-2800kg/m3
Specific gravity 2.65-2.80
Porosity 0.3-1.5%
Water absorption 0.16-0.40%
Hardness 3-4Mohs
UV resistance Excellent
Chemical resistance Excellent (non-calcareous); Poor (calcareous)
pH tolerance 3-14 (non-calcareous); 6-14 (calcareous)pH
Surface roughness 50-200 (natural riven)um
02 Mechanical
Tensile strength 15-30MPa
Compressive strength 50-200MPa
Flexural strength 39-60MPa
Shear strength 20-40MPa
Poisson's ratio 0.15-0.30
Impact resistance 3-8J
Creep resistance Excellent
03 Thermal
Thermal conductivity 1.49W/mK
Specific heat 760J/kgK
Thermal expansion 0.008-0.010mm/m/degC
04 Compliance & Fire First question
Combustibility class A1 Non-Combustible
Fire resistance level Assembly-dependent (non-combustible surface)minutes
Ignition temp N/A (does not ignite)degC
Flame spread index 0
Smoke dev. index 0
Heat release rate 0kW/m2
05 Sustainability & Health
Embodied carbon 0.006-0.058kg CO2-eq/kg
Carbon footprint 1-5kg CO2-eq/m2
Embodied energy 0.1-1.0MJ/kg
Water footprint 5-20L/kg
Recyclability 100%
Recycled content 0 (new); reclaimed available%
Renewable content 0%
Circular score 8.5/10
VOC emissions 0ug/m3
Toxicity rating Non-Toxic
LEED contribution 2-4points
06 Durability · Cost · Logistics
Expected lifespan 75-200+years
Maintenance interval 365 (annual inspection)days
Warranty period 30-100years
Sound absorption Low (0.05-0.10 NRC)
Material cost (range) 80-500AUD/m2
Material cost (per unit) 120-200AUD/m2
Lead time 7-90days
Lifecycle cost 400-700 (over 100 years)AUD/m2
Annual maintenance 1-3AUD/m2/year
Market availability Moderate (specialist import)
07 Assessment
Advantages
- Extraordinary longevity — 75-200+ years for S1 grade (Welsh Penrhyn guaranteed 100 years)
- Lowest embodied energy of all roofing materials — 0.1-1 MJ/kg, minimal processing
- Non-combustible (A1) without testing required — inherently fire-safe
- No chemical treatment, no factory process — split from natural stone
- Lowest lifecycle cost when amortised over service life
- Beautiful natural appearance that improves with age — no fading on quality slates
- Recyclable — second-hand slate widely reused in conservation
- Lowest thermal conductivity of building stones — natural insulating properties
Constraints
- Heavy — approximately 50-75 kg/m2, requiring structural verification of roof framing
- High initial cost — $200-500 AUD/m2 installed, premium product
- Specialist installation required — trained slaters, slow laying rate (1 square/day)
- Fragile before installation — individual slates crack if dropped or walked on
- Quality varies dramatically between quarries — S3 grade lasts only 20-40 years
- All supply imported to Australia — long lead times and shipping costs
- Difficult and costly to repair if underlying structure is damaged
08 Applications
A1 Pitched Roof Covering Natural split slate tiles nailed to timber battens for residential and commercial pitched roofs — the primary application achieving 75-200+ year service life
A2 Heritage Roof Restoration Matching replacement of original slate on heritage-listed buildings using Welsh, Spanish, or Canadian slate of equivalent type and quality
A3 Exterior Wall Cladding Hung slate tiles on exterior walls for weather protection and aesthetic effect — ventilated rainscreen or direct-fixed systems
A4 Interior Floor Tiles Honed or riven slate tiles for interior flooring applications — wet areas, entryways, kitchens — valued for slip resistance and durability
A5 Architectural Details Window sills, copings, thresholds, and feature cladding elements using cut-to-size natural slate
09 Sources & Standards
Sources pending — citations for this material are not yet recorded. Verify all figures against manufacturer data and current standards before specifying.