MATERIAL DATA SHEET

Sandstone Ashlar

Metamorphic/Sedimentary
mineral › Stone › Metamorphic/Sedimentary
natural-stonesedimentaryquartz-basedashlar-masonryheritage-constructionheritage-restorationAustralian-architectureHawkesbury-sandstoneSydney-sandstoneGosford-QuarriesHelidon-sandstonenon-combustibleASTM-C616load-bearingthermal-masssilica-hazarddimension-stoneEPD-certifiedlow-embodied-energybushfire-resistant
ATLAS CODE
MIN-STN-SED-004
Sandstone Ashlar
Category mineral
Material Family Stone
Density
2,000-2,650 kg/m3
Carbon (A1-A5)
0.06-0.12 kg CO2-eq/kg
Description

Sandstone ashlar is precision-cut dimensioned sandstone block used for load-bearing walls, facades, and heritage restoration in Australian architecture. A quartz-based sedimentary rock classified under ASTM C616 as Type I (sandstone, >60% free silica), Type II (quartzitic sandstone), or Type III (quartzite), sandstone has been Australia's defining architectural stone for over 200 years. Sydney's Hawkesbury sandstone — quarried from the Triassic-period formation of very pure silica grains bound by clay matrix — built the city's most iconic structures including St Mary's Cathedral, Sydney Town Hall, and the University of Sydney. Ashlar refers to the craft of dressing (cutting and finishing) stone into precise rectangular blocks with fine joints, distinguishing it from rubble masonry. Australian sandstone ranges from the cream-gold Gosford (NSW) and buff Helidon (QLD, also called Brisbane or Warrego sandstone) to the red-brown varieties from South Australia. Gosford Quarries, operating for over 100 years, is Australia's largest sandstone supplier. The stone's warmth, workability, and geological character make it irreplaceable for heritage conservation, though new quarrying faces environmental scrutiny and increasing rarity of premium deposits.

Embodied Carbon 0.06-0.12 kg CO2-eq/kg
Embodied Energy 0.1-1.0 MJ/kg
Advantages
Australia's most culturally significant building stone with 200+ year architectural traditionExcellent thermal mass and breathability — regulates indoor temperature and humidity naturallyBetter fire resistance than granite — withstands 800 degC without catastrophic spallingWorkable — can be carved, moulded, and dressed to precise profilesLow embodied energy — no firing or chemical processing requiredExceptional aesthetic warmth in cream, gold, buff, and rose-brown tonesLoad-bearing for low-rise construction — eliminates separate structural frameFully recyclable and salvageable — historic stone is routinely reused in restoration
Cautions
High cost, especially for heritage-grade Sydney sandstone (up to $10,000/m2 for rare deposits)Porous — vulnerable to salt crystallisation, rising damp, and efflorescence without proper detailingRequires skilled stonemasons — craft labour is scarce and expensiveQuarrying causes significant ecological damage (habitat destruction, landform alteration)Weathering limits exposed service life to 100-150 years for softer grades in polluted environmentsHeavy — structural implications for foundations and handling (2,000-2,650 kg/m3)Acid rain and atmospheric pollution accelerate surface decay of calcareous-cemented varieties
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TECHNICAL DATA: PERFORMANCE PROPERTIES MIN-STN-SED-004
Density (Dry) 2,000-2,650 kg/m3
Porosity 5-25 %
Water Absorption 1.0-8.0 %
Hardness 4-7 Mohs
Texture Options
Sawn (smooth machine-cut face, fine parallel marks visible)Honed (smooth rubbed finish, semi-polished)Bush-hammered (evenly textured, small point marks)Split-face/Rock-face (natural quarry split, rough projecting face)Tooled/Droved (parallel chisel marks, heritage technique)Picked (rough pointed texture)Rubbed (traditional hand-finished smooth surface)Shot-sawn (rough sawn with characteristic diagonal marks)
Pattern Options
Coursed ashlar (regular courses of equal height blocks)Random ashlar (blocks of varying height in courses)Broken ashlar (blocks of varying size with irregular joints)Squared rubble (roughly squared blocks in irregular courses)Block-in-course (alternating large and small blocks)Quoined corners (larger dressed blocks at wall corners)
Compressive Strength 27.6-137.9 MPa
Tensile Strength 2-6 MPa
Flexural Strength 2.4-12 MPa
Shear Strength 5-15 MPa
Elastic Modulus 6.5-20 GPa
Yield Strength 13-42 MPa
Impact Resistance moderate J
Bearing Capacity 2000-6000 kPa
Poisson's Ratio 0.10-0.30
Creep Resistance good
Abrasion Resistance moderate-to-good
Thermal Conductivity 1.5-4.2 W/mK
Thermal Resistance 0.05-0.13 m2K/W
Specific Heat Capacity 710-920 J/kgK
Thermal Expansion 0.007-0.012 mm/mK
Ignition Temperature N/A — non-combustible degC
Sound Transmission Class (STC) 50-55 STC
Noise Reduction Coeff. (NRC) 0.01-0.15
Optical
Solar Reflectance (SRI) 40-65

Sandstone has been used in construction for millennia — the Egyptian pyramids, Petra in Jordan, and medieval European cathedrals all utilised sandstone ashlar. In Australia, sandstone construction began with the First Fleet in 1788, with convict labour quarrying the readily available Hawkesbury sandstone for Sydney's earliest permanent structures. The 1810s-1880s represented the golden age of Australian sandstone construction, with architect Edmund Blacket and colonial engineer Mortimer Lewis designing landmark buildings in ashlar. Francis Greenway's Hyde Park Barracks (1819) and St Mary's Cathedral (1868-1928) exemplify the craft. The Pyrmont quarries, including the famous Hell Hole Quarry (closed c.1895), supplied much of early Sydney's stone. Post-WWII demolitions destroyed many sandstone buildings until the heritage conservation movement of the 1970s led to protective legislation. Gosford Quarries, established in the early 1900s in the Central Coast region, became Australia's primary commercial sandstone source. Today, sandstone ashlar is predominantly used for heritage restoration, prestige residential work, and institutional buildings where the material's cultural significance justifies the premium cost.

CLAD MATERIALS ATLAS PAGE 2 OF 4
SAFETY, ECOLOGY & INSTALLATION MIN-STN-SED-004
Ignition Temperature N/A — non-combustible degC
Embodied Carbon (A1-A3) 0.06-0.12 kg CO2-eq/kg
Embodied Energy 0.1-1.0 MJ/kg
Recyclability excellent %
Toxicity Classification safe-in-situ
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COMMERCIAL, LOGISTICS & REGULATORY MIN-STN-SED-004

DISCLAIMER: This specification document is generated from the CLAD Materials Atlas Database. Information is for general guidance only and does not constitute professional engineering advice. Values are typical and may vary by batch, manufacturer, and production run. Verify suitability for specific project applications independently.

ID: MIN-STN-SED-004 Schema: v3.0
CLAD MATERIALS ATLAS PAGE 4 OF 4