MATERIAL DATA SHEET

Interlocking concrete block, 390x190x190mm (190mm wall thickness)

Concrete Masonry Unit
mineral β€Ί Cementitious β€Ί Concrete Masonry Unit
mineralcementitiousconcrete-masonryinterlockingmortarlessdry-stackmasonrystructuralfire-resistantnon-combustibleacousticthermal-massretaining-wallloadbearingAS3700AS-NZS-4455adbriversalocaustral-masonrysustainablerecyclablesemi-skilled-installlandscapeboundary-wallresidentialnormal-weight
ATLAS CODE
MIN-CEM-CMU-006
Interlocking concrete block, 390x190x190mm (190mm wall thickness)
Category mineral
Material Family Cementitious
Regulatory Status Non-combustible (AS 1530.1)
Density
>1800 kg/m3
Carbon (A1-A5)
160 kgCO2e/mΒ²
Fire Class
Non-combustible (AS 1530.1)
Lifespan
100 yrs
Description

Interlocking dry-stack concrete masonry units (CMU) use a mechanical tongue-and-groove or surface-key interlock that aligns courses without conventional 10 mm mortar beds above the first course. The standard unit is nominally 390 x 190 x 190 mm (work size), corresponding to a face dimension of 400 x 200 mm on a 10 mm module. Matching half, end, corner and lintel units complete the system. Manufactured to AS/NZS 4455.1 and tested to AS/NZS 4456, the block achieves a minimum unit compressive strength of 10–20 MPa and a dry density above 1800 kg/mΒ³. Australian suppliers include Adbri Masonry (Versaloc 200 series) and Austral Masonry. The system suits retaining walls, loadbearing residential walling, boundary walls, garden structures and fire pits. Cores may be grouted and reinforced to AS 3700 for structural applications.

Primary Sectors
[Residential][Commercial][Industrial]
Typical Uses
  • Residential loadbearing walls
  • Retaining walls
  • Boundary and acoustic walls
  • Garden walls and raised beds
  • Steps and stair cheek walls
  • Fire pits and outdoor fireplaces
  • Commercial and industrial walling
Recycled Content 15
Renewable Content 0
Recyclability 100
Embodied Carbon 160 kgCO2e/mΒ²
Embodied Energy 1.1 MJ/kg
EPD Available Yes
Dimensional Tol. Β± [Β±2 mm] mm
Advantages
Mortarless dry-stack above first course β€” eliminates mortar mixing, reduces waste and speeds construction by 30–50 % compared with conventional CMU.Reduced skill requirement: semi-skilled crew can achieve acceptable alignment and plumb without experienced blocklayers.Self-aligning tongue-and-groove profile reduces the risk of course creep and provides consistent joint geometry.Minimum unit compressive strength 10–20 MPa (system dependent); grouted system characteristic compressive strength 10.2 MPa per AS 3700.FRL up to 180/180/180 (fully grouted system); integrity/insulation up to 240 min when fully corefilled.High thermal mass (190 mm grouted wall ~350 kg/mΒ²) supports passive solar design and reduces peak cooling loads.Acoustic performance Rw 56+ suitable for party walls and boundary applications.Non-combustible, inert β€” zero VOC, no off-gassing in service.Long service life (50–100+ years) with minimal maintenance.Readily available from national suppliers (Adbri, Austral Masonry); supply lead time 1–2 weeks.
Cautions
First course must be set in levelling screed or mortar to establish true datum β€” any error propagates through all courses.Dimensional tolerance Β±2 mm means minor face misalignment between courses; not suitable where flush fair-face finish is critical without grinding.Core percentage >30 % reduces net section area; grouting is required for all structural and fire-rated applications.FRL structural adequacy data is system-specific β€” consult manufacturer's Fire and Sound brochure; generic values do not apply.Heavier individual unit (~15.6 kg) than lightweight CMU alternatives; manual handling limits productivity for single-person crews.Limited range of surface textures and colours compared with standard CMU; specialist architectural finishes not generally available in interlocking profile.Grouting operations constrained to 5–40 Β°C ambient β€” cannot proceed in frost conditions.Cutting interlocking profiles with an angle grinder destroys the interlock feature; cut blocks must be placed at wall ends and corners where interlock is not required.Higher unit cost than conventional CMU (saving is on labour, not material); not cost-effective for small areas where setup overhead dominates.Not compatible with standard 10 mm mortar joint details; connection to adjacent mortared masonry, lintels and sills requires careful detailing.
CLAD MATERIALS ATLAS PAGE 1 OF 4
TECHNICAL DATA: PERFORMANCE PROPERTIES MIN-CEM-CMU-006
Density (Dry) >1800 kg/m3
Specific Gravity 2.0–2.2 (solid material)
Porosity 12–18 %
Water Absorption 6–10 %
Hardness 5–7 Mohs
Surface Roughness 50–200 um
UV Resistance Excellent
Chemical Resistance Good (alkali/water); Moderate (mild acid); Poor (strong acid, sulfate soils)
pH Tolerance 6–14 (service); pH 12.5–13.5 fresh pH
Available Colors
Natural grey (standard Portland cement colour)Off-white / cream (white cement or pigment β€” check supplier range)Terracotta / buff (iron oxide pigment β€” Adbri Versaloc colour range)Charcoal / dark grey (carbon black pigment)Custom colours available from Austral Masonry and Adbri for volume orders
Surface Finishes
As-manufactured (exposed aggregate texture)Bagged (sand-cement slurry fill rubbed back)Rendered and painted (fibre cement render or sand-cement render)Painted (masonry paint β€” alkali-resistant primer required for new concrete)Penetrating silane/siloxane sealer (transparent, water repellent)Architectural block (factory-applied paint or integrally coloured unit)
Texture Options
Smooth (steel mould finish) β€” standardSplit face (mechanically fractured aggregate texture, available from some suppliers)Sandblasted (post-manufacture, enhances aggregate texture)Painted or sealed (various finishes over smooth or split face)
Pattern Options
Running bond (standard, most common)Stack bond (requires engineering approval for structural walls β€” reduced shear capacity)Ashlar pattern (using half and standard units alternated)Coursed random with different unit heights where system allows
Compressive Strength 10–20 MPa
Tensile Strength 0.1–0.3 (unreinforced); reinforcement required for tensile loads MPa
Flexural Strength 0.20–0.36 MPa
Shear Strength 0.05–0.15 (ungrouted dry-stack); 0.3–0.6 (grouted reinforced) MPa
Elastic Modulus 4–10 GPa
Impact Resistance Good (low-velocity); Moderate (hard-point impact β€” face spalling) J/m
Bearing Capacity N/A β€” governed by foundation soil kPa
Poisson's Ratio 0.15–0.20
Creep Resistance Good β€” low creep at service loads
Abrasion Resistance Moderate–Good
Thermal Conductivity 0.5–1.3 W/mK
Thermal Resistance 0.15–0.35 (block only) m2K/W
Specific Heat Capacity 840–1000 J/kgK
Thermal Expansion 8–12 x10^-6/C
Melting Point N/A β€” non-combustible; decomposes >600 C C
Sound Transmission Class (STC) 56+ Rw
Noise Reduction Coeff. (NRC) 0.02–0.05 NRC
Impact Insulation Class (IIC) N/A IIC
Optical
Light Transmittance 0 %
Light Reflectance (LRV) 40–55 (grey); 60–75 (light colours) %
Solar Reflectance (SRI) 25–35 (grey); 55–75 (light) SRI
Electrical
Electrical Conductivity ~10^-9 S/m

Mortarless or dry-stack masonry has ancient precedents β€” Inca dry-stone construction and Egyptian pyramid casing stones used tight mechanical fits without mortar. Modern interlocking concrete masonry systems emerged in the 1970s–1980s as manufacturers sought to reduce the skilled labour component of blockwork. Early proprietary systems (Sparlock, Azar block) used surface keys or interlocking ledges; by the 1990s normal-weight CMU systems with moulded tongue-and-groove profiles were commercially available across North America, Europe and Australia. The introduction of AS/NZS 4455.1 (masonry units) and AS 3700 (masonry structures) provided a regulatory framework for structural interlocking CMU in Australia. Adbri Masonry's Versaloc system and Austral Masonry's interlocking range are the principal contemporary Australian products, supplying residential, commercial and landscaping markets. Ongoing development focuses on improved surface texture, wider colour range and integration with AAC panels for hybrid wall systems.

CLAD MATERIALS ATLAS PAGE 2 OF 4
SAFETY, ECOLOGY & INSTALLATION MIN-CEM-CMU-006
Flame Spread Index 0
Smoke Developed Index 0
Combustibility Class Non-combustible (AS 1530.1)
Fire Resistance Rating FRL 180/180/180 (grouted 190 mm system); up to 240/240/240 fully corefilled minutes
Heat Release Rate 0 kW/m2
Toxicity of Combustion Non-toxic β€” no combustion products from masonry substrate
Embodied Carbon (A1-A3) 160 kgCO2e/mΒ²
Embodied Energy 1.1 MJ/kg
Water Footprint 180 L/kg
EPD Available Yes
Recycled Content 15%
Renewable Content 0%
LEED Points 3
Circular Economy Score 7.5 /100
VOC Emissions 0 g/L
Skill Level semi-skilled (general); skilled (first course and grouted structural walls)
Crew Size 2
Installation Time 700 hr/mΒ²
Curing Time 0 hours
Setting Time 24 min
Temperature Range 5–40 C (grouting); unrestricted (dry-stack only) Β°C
Humidity Range 10–95% (dry-stack); 40–85% (grouting) %
Required Tools
Spirit level (1.2 m minimum) for first course and periodic plumb checksString line and pins for alignment of each courseRubber mallet for seating blocks onto interlock profileMortar board, trowel and float for first-course levelling screedAngle grinder with diamond blade for cut blocks at ends and penetrationsReinforcement bar (N12 or N16) and plastic spacer chairs for grouted structural wallsConcrete pump or grout bucket and vibrator for core groutingTape measure and chalk line for layoutSafety glasses, gloves and hearing protection (cutting)
Certifications Required
General construction induction (White Card) for site workersWorking at heights certification if wall exceeds 2 m and elevated platforms are usedStructural engineer inspection for walls designed to AS 3700Building permit may be required for walls >1 m height (jurisdiction dependent β€” check local council)
Weather Limitations
First course mortar must not be placed in rain or below 5 Β°CCore grouting suspended below 5 Β°C or above 40 Β°C ambientProtect freshly grouted cores from rain for 24 hoursStrong wind (>25 km/h) can destabilise ungrouted tall walls during construction β€” temporary propping requiredAvoid laying in direct sun at temperatures >35 Β°C without shade protection for grout
CLAD MATERIALS ATLAS PAGE 3 OF 4
COMMERCIAL, LOGISTICS & REGULATORY MIN-CEM-CMU-006
Material Cost $4–8 AUD per block
Installation Cost $30–55 AUD/m2 (labour only)
Annual Maintenance $0.30–1.00 AUD/m2/year
Lifecycle Cost (50yr) $350–500 AUD/m2 (50-year LCC)
Market Availability moderate–good (major cities); moderate (regional)
Lead Time 1–2 weeks (standard); 2–3 weeks (regional or specialty) weeks
Supply & Logistics
MOQ 1 pallet (approximately 60 units). Volume discounts typically available for 10+ pallets.
Design Life 100 years
Maintenance Interval 10 months
Service Temp Range -20 to 70 C Β°C
Freeze/Thaw Resistance excellent
Dimensional Stability excellent

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-CEM-CMU-006 Schema: v3.0
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