mineral / Stone / Metamorphic Stone

Welsh slate roofing

Traditional Welsh slate roofing material offering exceptional durability, low water absorption, and distinctive appearance for Australian heritage and contemporary applications.

Atlas code
MIN-STN-MET-003
mineralstonemetamorphicroofingheritagepremiumWelsh
Welsh slate roofing
At-a-glance signals

Traditional Welsh slate roofing material offering exceptional durability, low water absorption, and distinctive appearance for Australian heritage and contemporary applications.

Overview
Executive summary

Welsh slate is a fine-grained metamorphic rock formed over 500 million years ago in Wales. Renowned for its durability, low porosity, and distinctive grey-blue color, it remains the premium roofing material for high-end residential and heritage projects. The material offers exceptional weather resistance, minimal maintenance requirements, and a lifespan exceeding 100 years when properly installed.

Best when…
  • Exceptional durability (100+ years)
  • Very low water absorption
  • Distinctive aesthetic
  • Minimal maintenance
  • Fire resistant
  • Weather resistant
  • Traditional craftsmanship
Top advantages
  1. 01 Exceptional durability (100+ years)
  2. 02 Very low water absorption
  3. 03 Distinctive aesthetic
  4. 04 Minimal maintenance
  5. 05 Fire resistant
Top limitations
  1. 01 High cost due to import
  2. 02 Skilled installation required
  3. 03 Heavy weight
  4. 04 Limited supply
  5. 05 Long lead times
Technical
Physical ·7
Density
2700 kg/m³ range: 2600-2800
Specific gravity
2.7
Porosity
0.5 % range: 0.3-0.7
Water absorption
0.35 %
Hardness
3.5
UV resistance
Excellent - Natural stone, no UV degradation
Chemical resistance
Excellent - Resistant to acid rain, salt spray
Mechanical ·4
Tensile strength
12 MPa range: 7-20
Compressive strength
150 MPa range: 100-200
Flexural strength
50 MPa range: 40-70
Impact resistance
Good - varies with thickness
Sustainability & Health
Embodied carbon & energy ·5
Embodied carbon
157 kgCO2e/m² For 10mm thickness at 2700kg/m³
Carbon footprint
0.058 kgCO2e/kg Lowest among roofing materials
Embodied energy
1 MJ/kg Minimal processing required
Renewable content
0 % Non-renewable geological material
Circular score
85 High reuse potential
Compliance & Fire
Fire performance ·5
Combustibility class
Non-combustible to AS 3959
Fire resistance level
Non-combustible
Ignition temp
N/A - Non-combustible °C
Flame spread index
0
Smoke dev. index
0
Cost & Lifecycle
Capex & lead time ·6
Material cost (range)
130 – 150 $/m² Material only
Material cost (per unit)
140 $/m²
Lead time
6 weeks
Lifecycle cost
3.5 $/m²/year Over 100 years
Annual maintenance
0.5 $/m²/year
Market availability
Readily available - Import required
Service life & durability ·3
Expected lifespan
100 years range: 75-150+
Maintenance interval
5 years Visual inspection only
Warranty period
30 years Varies by supplier
Layer D

Where it's used

Heritage building restoration
Premium residential roofing
Churches and cathedrals
Government buildings
Luxury homes
Traditional architecture
Conservation projects
MIN-STN-MET-003 · Materials Atlas · CLAD Atlas data is reference-only. Verify against manufacturer specifications and current standards before specifying.