Choosing an external wall system is one of the earliest and most consequential decisions on any project. The choice locks in day-one cost, ongoing maintenance obligations, thermal and acoustic performance, and fire compliance for the life of the building. Getting it wrong is expensive to fix.
This post compares five systems commonly used in Australian residential and commercial construction: face brick, rendered masonry, fibre cement sheet, metal cladding, and Hebel (autoclaved aerated concrete panel). Each is assessed on upfront cost, maintenance, thermal performance, acoustic performance, and fire resistance.
The Five Systems at a Glance
Face brick is a full-thickness or veneer masonry wall using clay or concrete bricks with exposed face. Rendered masonry uses the same substrate but adds a cement or polymer render coat, typically painted. Fibre cement sheet (brands such as James Hardie Scyon or Villaboard) is a lightweight panel fixed to a framed wall, usually painted. Metal cladding covers a range of profiles including corrugated steel, Trimdek, Spandek and concealed-fix systems in COLORBOND steel, fixed to a framed wall with a cavity. Hebel PowerPanel is an AAC (autoclaved aerated concrete) panel system that can be used as a structural or non-structural external wall, typically painted or rendered.
Upfront Cost
Material and labour costs vary by region, project complexity and finishes, but the general order from lowest to highest installed cost per square metre is roughly:
- Metal cladding on a framed wall: $80 to $150/m²
- Fibre cement sheet on a framed wall: $90 to $160/m²
- Hebel panel system: $130 to $200/m²
- Rendered masonry: $180 to $280/m² (including block or brick substrate and render)
- Face brick veneer: $200 to $320/m²
These are indicative supply-and-install figures for 2025 to 2026 and will shift with labour markets and material costs. The key point is that face brick and rendered masonry carry a significant upfront premium over lightweight cladding systems.
That premium is partly offset over time, which is why lifetime cost matters more than day-one price.
Maintenance and Repaint Cycles
This is where the comparison changes substantially.
Face brick requires no painting. Periodic repointing (every 20 to 40 years depending on exposure and mortar quality) is the main maintenance item. In coastal or industrial environments, brick cleaning may be needed. The maintenance cost over a 30-year period is low.
Rendered masonry is painted, and paint fails. A quality exterior paint system on render typically needs repainting every 8 to 12 years, depending on climate, colour and paint specification. Each repaint cycle on a two-storey home can cost $5,000 to $15,000 in labour and materials. Over 30 years, that is two to three full repaints, adding $10,000 to $45,000 to the lifetime cost before you account for any render cracking repairs.
Fibre cement sheet follows a similar repaint cycle to render: 8 to 12 years for a quality acrylic or texture coat system. The substrate is more dimensionally stable than render over masonry, so cracking is less common, but the paint obligation is the same.
Metal cladding in COLORBOND steel carries a Bluescope paint warranty (typically 10 to 12 years for the colour coat, 25 years for the steel substrate against perforation in standard environments). In practice, the factory-applied paint system on COLORBOND steel outlasts site-applied paint on fibre cement or render in equivalent conditions. Repainting is not routine maintenance in the way it is for the other systems, though it may be required after 15 to 25 years depending on exposure zone and colour choice.
Hebel panels must be painted or rendered. The maintenance obligation is similar to rendered masonry: expect an 8 to 12 year repaint cycle. Hebel does not crack as readily as sand-cement render, but the paint film still degrades.
The practical conclusion: if you are comparing face brick at $280/m² installed against fibre cement at $130/m² installed, factor in two or three repaints over the building's life before declaring fibre cement the cheaper option.
Thermal Performance
Masonry walls (brick, rendered block, Hebel) have thermal mass. They absorb heat during the day and release it at night, which can reduce peak cooling loads in climates with large diurnal temperature swings. This effect is most useful in inland temperate and semi-arid climates. In humid coastal climates where nights stay warm, thermal mass offers less benefit.
Lightweight cladding systems (fibre cement, metal) have negligible thermal mass. Their thermal performance depends almost entirely on the insulation and cavity behind them. A 90mm stud wall with R2.5 bulk insulation batts and a reflective sarking layer behind metal cladding will outperform an uninsulated brick veneer wall in most NCC 2025 energy calculations. The wall system is the weather barrier; the insulation does the thermal work.
This distinction matters when reading NCC 2025 compliance pathways. The Deemed-to-Satisfy provisions require minimum total R-values for external walls that vary by climate zone. A lightweight framed wall with appropriate insulation can meet or exceed the same R-value as an insulated masonry wall, often at lower cost.
Hebel has a higher inherent R-value than dense clay brick (approximately R0.5 to R1.0 for a 75mm panel versus R0.2 for a 110mm brick), but both require added insulation to meet NCC 2025 requirements in most climate zones.
Acoustic Performance
Mass is the primary driver of airborne sound reduction in walls. Dense masonry walls perform well against external noise: a 110mm brick veneer wall typically achieves an Rw of around 45 to 50 dB, and a 200mm concrete block wall can reach Rw 50 to 55 dB.
Lightweight framed walls with fibre cement or metal cladding achieve lower mass-based sound reduction, but the gap can be narrowed with acoustic insulation batts (such as glasswool or rockwool), resilient mounts, and double-leaf construction. A well-specified lightweight wall can reach Rw 40 to 45 dB, which is adequate for most residential applications away from major roads or flight paths.
Hebel sits between lightweight and dense masonry. A 75mm Hebel panel has a surface density of around 50 kg/m², compared to around 200 kg/m² for a 110mm brick skin. Acoustic performance is moderate and benefits from added insulation in the cavity.
For projects near busy roads, rail corridors, or in mixed-use buildings, acoustic performance should be modelled by an acoustic consultant rather than assumed from generic product data.
Fire Resistance and Non-Combustibility
Fire performance is where the regulatory picture becomes specific and non-negotiable.
Face brick, rendered masonry and Hebel are non-combustible materials. They comply with non-combustibility requirements under AS 1530.1 and are suitable for use in buildings of any construction type under the NCC, including Type A (generally buildings over three storeys) and Type B construction.
Fibre cement sheet is classified as non-combustible under AS 1530.1 when tested in standard sheet form without coatings. This makes it acceptable for use in external walls of Type A and Type B buildings, subject to the specific product being tested and listed. Check the product's CodeMark or fire test certificate before specifying in a multi-storey or commercial application.
Metal cladding in COLORBOND steel is non-combustible. The steel substrate meets non-combustibility requirements. However, the wall system as a whole, including any insulation, cavity barriers, and substrate materials, must be assessed for compliance with NCC 2025 requirements for external walls in Type A and Type B buildings. NCC 2025 introduced tighter requirements for external wall systems following the attention on combustible cladding failures in Australia and internationally. Mineral wool insulation (non-combustible) is preferred over EPS or PIR foam in these applications.
For Class 2 to 9 buildings (apartments, commercial, aged care), the non-combustibility of every layer in the wall assembly must be confirmed, not just the face material. Specifiers should obtain fire test reports for the complete system, not individual components.
For BAL-rated sites under AS 3959, the cladding material and its fixing method must meet the relevant BAL requirements. Metal and fibre cement cladding are generally suitable across BAL ratings with appropriate detailing. Timber-framed walls with combustible elements require careful attention at higher BAL ratings.
Comparing the Five Systems Side by Side
| System | Upfront Cost | Repaint Cycle | Thermal Mass | Acoustic Mass | Non-Combustible |
|---|---|---|---|---|---|
| Face brick | High | None | High | High | Yes |
| Rendered masonry | High | 8 to 12 years | High | High | Yes |
| Fibre cement | Low to medium | 8 to 12 years | Low | Low to medium | Yes (check product) |
| Metal cladding | Low to medium | 15 to 25 years | Low | Low | Yes (steel substrate) |
| Hebel AAC | Medium | 8 to 12 years | Medium | Medium | Yes |
Which System Suits Which Project?
For a detached house in a temperate climate where the owner plans to stay for 30 years, face brick veneer often delivers the lowest lifetime cost despite the highest day-one price. No repainting, no render cracking, and low maintenance.
For a project home or investment property where upfront cost is the binding constraint, fibre cement or metal cladding on a framed wall with quality insulation will meet NCC 2025 energy requirements and carry a lower purchase price. Budget for repaints.
For a multi-storey residential or commercial project, non-combustibility of the full wall assembly is the starting point, not an afterthought. Brick, Hebel and tested fibre cement systems are the straightforward paths. Metal cladding systems can comply but require careful specification of all layers.
For bushfire-prone sites, confirm the full assembly against AS 3959 requirements for the relevant BAL rating before finalising the specification.
Sourcing Metal Cladding and Wall Framing Materials
If metal cladding is in your wall specification, ACS supplies COLORBOND steel profiles including corrugated, Trimdek, Spandek and concealed-fix options, along with steel battens, top hats and C/Z purlins for framing and fixing systems. Custom cut-to-length sheets and flashings are available, with delivery of long materials nationwide.
For project pricing or trade account enquiries, visit acsupplies.com.au or request a quote directly through the site.