composite / Panelised / Insulated Panel
Insulated Metal Panel (IMP), PIR or Mineral Wool Core (50mm, 75mm, 100mm, 125mm, 150mm, 200mm)
Factory sandwich panels with steel skins and PIR (lambda 0.022 W/mK, R2.3–R9.1) or mineral wool cores (lambda 0.033 W/mK, non-combustible Group 1/A1). Mineral wool mandated in Type A/B construction post-NCC 2022 amendments.
Atlas code
COM-PNL-INS-006
At-a-glance signals
Factory sandwich panels with steel skins and PIR (lambda 0.022 W/mK, R2.3–R9.1) or mineral wool cores (lambda 0.033 W/mK, non-combustible Group 1/A1). Mineral wool mandated in Type A/B construction post-NCC 2022 amendments.
Overview
Executive summary
Insulated Metal Panels (IMPs) are factory-engineered sandwich panels comprising two profiled steel skins — typically 0.4–0.7mm Colorbond or Zincalume steel — bonded to a continuous insulating core. Two core technologies dominate the Australian market: polyisocyanurate (PIR) foam and mineral wool (rock wool or slag wool). PIR cores deliver superior thermal performance with a declared conductivity of 0.022 W/mK, yielding total panel R-values from approximately R2.3 (50mm) to R9.1 (200mm). Mineral wool cores offer a lower thermal conductivity of 0.033 W/mK but are non-combustible (Euroclass A1, AS 1530.1 Group 1), making them the mandated choice in fire-sensitive Type A and B construction following post-Grenfell and post-Lacrosse NCC amendments. Panel widths typically span 900–1200mm with custom lengths to 14m, and they interlock via tongue-and-groove or concealed clip joints. Major Australian brands include Kingspan (QuadCore, KS1000 RW), Lysaght Bondor (MetecnoPanel, SolarSpan), and Metecno. IMPs are used predominantly for commercial and industrial wall cladding and roofing, cold-storage facilities, and increasingly for medium-density Type C residential construction where PIR cores remain permissible.
Best when…
- Integrated building envelope — structure, insulation, weather barrier, and lining in one element
- High thermal performance: PIR panels achieve R2.3–R9.1 (50–200mm) in a single skin
- Mineral wool core is non-combustible (Group 1/A1) — compliant with NCC Type A and B walls
- Rapid installation: 3–5 times faster than equivalent framed-and-insulated wall construction
- Factory manufacture ensures consistent quality and dimensional precision
- Wide span capability (up to 8m wall, 6m roof unsupported) reduces secondary structure
- Colorbond steel skins provide 10–25 year paint warranty (Bluescope warranty conditions)
- Fire resistance ratings up to FRL 60/60/60 achievable with mineral wool panels and linings
- Acoustic STC 30–38 for mineral wool wall panels — suitable for industrial noise environments
- Fully recyclable steel skins; high recycled content in mineral wool core (up to 70% recycled slag)
Top advantages
- 01 Integrated building envelope — structure, insulation, weather barrier, and lining in one element
- 02 High thermal performance: PIR panels achieve R2.3–R9.1 (50–200mm) in a single skin
- 03 Mineral wool core is non-combustible (Group 1/A1) — compliant with NCC Type A and B walls
- 04 Rapid installation: 3–5 times faster than equivalent framed-and-insulated wall construction
- 05 Factory manufacture ensures consistent quality and dimensional precision
Top limitations
- 01 PIR core is combustible — prohibited in Type A/B external walls above NCC thresholds
- 02 Post-Grenfell regulatory scrutiny creates procurement and insurance complexity for PIR systems
- 03 Mineral wool core adds 3–7 kg/m2 weight versus PIR equivalent
- 04 Thermal bridging at fasteners and joints can reduce system R-value by 10–20%
- 05 Specialist trade knowledge required — incorrect joint sealing causes condensation and corrosion
Technical
Physical ·9
- Density
- PIR core: 32–45 kg/m3; mineral wool core: 80–120 kg/m3; steel skins: ~7850 kg/m3; composite panel: 8–25 kg/m2 depending on core type and thickness kg/m³
- Specific gravity
- 0.010–0.035 (panel composite) Composite panel specific gravity varies significantly with core type; PIR panels ~0.010–0.020; MW panels ~0.020–0.035
- Porosity
- PIR: ~95 (closed-cell); MW: ~85–90 (open fibre) % PIR foam: closed-cell, ~95% closed cells; mineral wool: open-fibre matrix ~85–90% air by volume
- Water absorption
- PIR core: <3 (closed-cell); MW core: <5 (protected); exposed MW: can absorb significantly % PIR closed-cell foam: <3% by volume (ASTM C209). Mineral wool: low when protected by steel skins but can absorb if exposed at cut edges or open joints. Steel skins: zero.
- Hardness
- Steel skin Rockwell B ~60; PIR core Shore D 25–35 Shore Steel skin hardness not typically rated; PIR core Shore D ~25–35; mineral wool is fibrous and does not have a meaningful Shore rating
- UV resistance
- Excellent (Colorbond steel skins) Steel skins with Colorbond PVDF paint: excellent UV resistance. Core materials not exposed to UV in service. Colorbond Ultra rated for tropical and coastal environments.
- Chemical resistance
- Good (Colorbond skins); Excellent (MW core) Colorbond steel: good resistance to mild acids, alkalis, and solvents. PIR core: resistant to water, dilute acids; degraded by strong solvents. MW core: inert to most chemicals.
- pH tolerance
- 5–9 (uncoated steel); Colorbond coating extends to 4–10 pH Steel skins susceptible to corrosion below pH 5 or above pH 9; Colorbond coating extends tolerance
- Surface roughness
- 0.8–3.5 (steel skin, profile dependent) μm Ra Depends on steel skin profile. Micro-rib Colorbond: ~1.5–3.5 μm Ra. Flat liner panels: ~0.8–1.5 μm Ra.
Mechanical ·7
- Tensile strength
- 550–600 (steel skin); PIR core: 0.08–0.12 MPa perpendicular MPa Steel skin tensile strength: 550–600 MPa (G550). PIR core tensile perpendicular to face: 80–120 kPa. Core tensile governs pull-through resistance of fasteners.
- Compressive strength
- PIR core: 100–150 kPa; MW core: 40–60 kPa (perpendicular to face) kPa Core compressive strength (perpendicular to face): PIR foam 100–150 kPa (density 40–45 kg/m3). Mineral wool 40–60 kPa. Avoid point loads on panel face without load-spreading plates over MW panels.
- Flexural strength
- Panel system — refer to manufacturer span tables per AS/NZS 1170.2 kNm/m Composite flexural capacity depends on panel as structural element. Representative values: 100mm PIR wall panel at 3m span resists ~1.0–1.5 kPa wind load. Refer to manufacturer span tables for design values.
- Shear strength
- PIR core: 70–150 kPa; MW core: 40–80 kPa kPa Core shear strength critical for panel spanning. PIR core: 70–150 kPa (density dependent). Mineral wool core: 40–80 kPa. Governs span table calculations per AS/NZS 1170.2.
- Poisson's ratio
- 0.30 (steel skins, governing) Steel skins: 0.30. PIR foam core: ~0.35. MW core: ~0.20–0.25.
- Impact resistance
- 10–30 J (Colorbond skin, thickness dependent) J Steel skins resist moderate impact. Colorbond 0.55mm skin: dents at ~10–20J localised impact. Heavier 0.7mm skins in traffic-exposed zones. Core materials do not contribute to impact resistance.
- Creep resistance
- Good (steel skins); Moderate (PIR core under sustained load) Steel skins: excellent creep resistance. PIR foam: some creep under sustained compressive load — avoid point loads on core without load-spreading plates. MW core: better creep resistance than PIR under sustained load.
Sustainability & Health
Embodied carbon & energy ·7
- Embodied carbon
- 18–35 kgCO2e/m2 (100mm panel, cradle-to-gate, core type dependent) kgCO2e/m² Indicative embodied carbon (cradle-to-gate): PIR panel 100mm: ~18–28 kgCO2e/m2 (steel skins ~15–20, PIR core ~3–8). MW panel 100mm: ~20–35 kgCO2e/m2 (MW core slightly higher than PIR). Steel skin embodied carbon dominates. Kingspan EPDs available per EN 15804.
- Carbon footprint
- 18–35 kgCO2e/m2 (embodied); operational savings offset in 3–8 years kgCO2e/m² See embodiedCarbon. Operational carbon savings from high R-value significant over panel lifetime — typically offsetting embodied carbon within 3–8 years in Australian climate zones.
- Embodied energy
- Panel total: ~150–500 MJ/m2 (thickness and core dependent) MJ/kg PIR foam core: high embodied energy ~80–120 MJ/kg (petrochemical origin). Mineral wool core: ~15–25 MJ/kg (can use up to 70% recycled slag). Steel skin: ~25–35 MJ/kg (recycled content 50–85%). Composite panel total: ~150–500 MJ/m2 depending on thickness and core.
- Water footprint
- 200–500 L/m2 (100mm panel, manufacturing) L/m² Steel manufacturing is water-intensive (~50–150 L/kg steel). PIR foam manufacturing: moderate water use. MW manufacturing: moderate. Overall panel water footprint ~200–500 L/m2 (100mm panel).
- Recycled content
- Steel skins: 50–85%; MW core: up to 70% recycled slag; PIR core: 0% % Steel skins: 50–85% recycled steel content (Bluescope uses ~50% recycled scrap in Colorbond). Mineral wool core: up to 70% recycled slag (industrial by-product). PIR core: 0% recycled content (virgin petrochemical).
- Renewable content
- 0 % No renewable materials in standard IMP construction.
- Circular score
- 5/10 (steel recyclable; foam core problematic) /10 Steel skins fully recyclable at end of life (high value scrap). PIR foam: difficult to recycle — landfill typically. MW core: technically recyclable but limited collection infrastructure. Overall: steel recyclability is a significant positive.
Compliance & Fire
Fire performance ·6
- Combustibility class
- MW core: Group 1 (AS 1530.1), Euroclass A1 — non-combustible. PIR core: Group 2–3 (combustible), Euroclass B-s2,d0 CRITICAL DIFFERENTIATION. Mineral wool core: non-combustible per AS 1530.1, Group 1 (AS 3959/NCC), Euroclass A1 — compliant for Type A and B external walls. PIR core: combustible, Group 2–3 (AS 3959/NCC), Euroclass B-s2,d0 at best — PROHIBITED on external walls of Type A and B buildings exceeding NCC 2019+ height thresholds unless full system passes AS 5113. Post-Grenfell NCC amendments (effective 2019 in most states) make core type selection a critical compliance decision. Some states (VIC, NSW, QLD) have additional cladding regulations beyond base NCC.
- Fire resistance level
- MW wall panels: up to FRL -/60/60 or -/90/90 (with tested linings); PIR panels: typically unrated without passive protection minutes FRL of IMP wall assemblies (per AS 1530.4): mineral wool core panels with additional linings can achieve FRL -/60/60 or -/90/90 (load-bearing wall ratings). Proprietary systems tested by Kingspan (KS1000 RW) and Bondor. PIR core panel assemblies generally cannot achieve FRL without significant additional passive protection. Roof panels: not typically rated for FRL.
- Ignition temp
- PIR foam: 340–380; MW core and steel skins: non-igniting °C PIR foam self-ignition temperature: ~340–380°C. Steel skins do not ignite. Mineral wool does not ignite (non-combustible).
- Flame spread index
- MW core panels: FSI 0 (Group 1); PIR core panels: FSI 15–25 (exposed core) FSI Mineral wool core panels: FSI 0 (non-combustible per AS 1530.3, Group 1). PIR core panels: FSI typically 15–25 for exposed foam; panel system flame spread governed by AS 5113 test configuration.
- Smoke dev. index
- MW core panels: SDI ~0; PIR core (exposed): SDI 5–15 (significant smoke) SDI Mineral wool panels: SDI ~0 (non-combustible). PIR core (exposed): significant smoke development — typically s2 classification (Euroclass, medium smoke). Dense black smoke produced during PIR combustion.
- Heat release rate
- PIR core (exposed): 50–200 kW/m2; MW core: near zero kW/m² PIR core peak HRR: 50–200 kW/m2 (core exposed, AS ISO 9705 test). Panel system HRR depends on exposure configuration and skin restraint. Mineral wool core: near-zero HRR — non-combustible.
Cost & Lifecycle
Capex & lead time ·6
- Material cost (range)
- PIR wall panels: $55–95/m2; MW wall panels: $80–150/m2 (supply only, AUD, 2025) AUD/m² Supply-only indicative Australian market pricing (2025): PIR core wall panels 75mm: $55–80/m2; PIR 100mm: $65–95/m2; MW core wall panels 100mm: $80–120/m2; MW 150mm: $100–150/m2. Roofing panels typically 10–15% less than wall. Prices vary with order volume, colour, and profile.
- Material cost (per unit)
- $55–150/m2 (supply only, core type and thickness dependent) AUD/m² See materialCostRange. Per-unit pricing at distributor level for indicative budgeting.
- Lead time
- 2–12 (thickness, colour, and core type dependent) weeks Stock thicknesses (75mm, 100mm) in common Colorbond colours: 2–4 weeks. Non-stock thicknesses (125mm, 150mm, 200mm) or special colours: 6–12 weeks. Custom profiles or mineral wool panels: 8–12 weeks. Import lead times apply for some Kingspan products.
- Lifecycle cost
- 15–25% lifecycle saving versus equivalent framed wall (30-year basis) AUD/m² LCC IMP lifecycle cost advantage stems from reduced energy costs (high R-value), rapid installation (reduced labour), and 30–50 year service life with minimal maintenance. Estimated 15–25% lifecycle cost saving versus equivalent framed-and-insulated wall over 30 years.
- Annual maintenance
- 0.50–2.00 AUD/m²/year Minimal routine maintenance — annual visual inspection and periodic sealant replacement (~10–15 year interval). Colorbond surface cleaning in coastal environments. Estimated annual maintenance cost $0.50–2.00/m2/year.
- Market availability
- PIR core: widely available; MW core: good availability (some lead time premium) PIR core IMPs: widely available nationally from Kingspan, Bondor/Lysaght, Metecno with established distributor networks. Mineral wool core IMPs: good availability from Kingspan KS1000 RW series and Metecno Fire-Zero; slightly longer lead times. Regional availability may vary — metropolitan construction typically superior supply.
Service life & durability ·3
- Expected lifespan
- 30–50 years Panel system expected service life 30–50 years with correct joint maintenance and Colorbond steel skins. Coastal environments require more frequent inspection. PIR core does not degrade significantly in service if moisture-protected.
- Maintenance interval
- 6–12 (coastal); 12–24 (inland) months Visual inspection of joints, sealants, and fasteners annually. Sealant replacement typically required every 10–15 years. Colorbond surface cleaning 6–12 months in coastal environments.
- Warranty period
- 10–25 (Colorbond paint); 36 (Zincalume substrate) years Colorbond steel paint warranty: 10–25 years (coastal and standard environments, Bluescope conditions). Panel structural integrity: typically 10-year manufacturer warranty. Colorbond Zincalume substrate: 36-year anti-perforation warranty.
Layer D
Where it's used
Commercial and industrial external wall cladding
Low-pitch industrial roofing
Cold storage and controlled environment rooms
Commercial office and retail facades (Type B, MW core)
School and education buildings
Healthcare facilities
Data centres
Modular and transportable buildings
Agricultural buildings
Residential construction (Type C, single dwellings)