Fibre Reinforced Facade Encyclopedia: Materials
Cladding panels are prefabricated sheets, tiles or moulded units fixed to a building’s structure to form its outer skin. They are not structure. They carry their own weight and wind load back to the frame and do nothing else, which is what separates cladding from a load-bearing wall. This page is about choosing the panel material; for how a panel is carried, jointed and weathered once the material is settled, see facade panels.
The same 1,200 by 3,000 mm panel weighs about 18 kg in FRP, about 160 kg in GRC with ribs, and about 1,300 kg in 150 mm precast concrete. The material decision is a structural decision.
At a glance
| Property | Typical value | Note |
|---|---|---|
| Fibre reinforced polymer (FRP) | 5 to 32 kg/m² | Lightest; polymer composite, not non-combustible |
| Glass fibre reinforced concrete (GRC, GFRC) | 30 to 50 kg/m² | Cementitious; can be tested non-combustible |
| Glass fibre reinforced gypsum (GRG, GFRG) | about 23 kg/m² | Interior only; not a weather-exposed material |
| Fibre cement sheet | 16 to 30 kg/m² | Flat sheet formats; deemed non-combustible in the NCC list |
| Aluminium composite panel (ACP) | 5 to 8 kg/m² | Core material decides fire behaviour; PE core is prohibited in practice |
| Terracotta and ceramic | 30 to 45 kg/m² | Modular tile formats, fixed to rails |
| Natural stone, 30 mm | 75 to 90 kg/m² | Undercut anchors; thickness set by flexural test |
| Precast concrete, 100 to 200 mm | 240 to 480 kg/m² | Can be load-bearing; needs a structure sized for it |
| UHPC | 55 to 120 kg/m² | Thin high-strength concrete; between GRC and precast |
| Typical facade wind pressure | 0.5 to 3.0 kPa | AS/NZS 1170.2; governs panel span and fixing count |
What counts as a cladding panel
A cladding panel is any prefabricated element applied to the outside of a structural frame or wall to form the weather-facing surface. The category runs from a 5 mm flat sheet screwed to top-hat battens up to a 12 square metre moulded unit craned onto cast-in anchors. What they share is that the panel is supported by the building rather than supporting it, and that it is made in a factory rather than formed in place.
The distinction matters for code. Because cladding is not structure, its failure mode is falling off or catching fire rather than collapse, and the provisions that apply to it are about attachment under AS/NZS 1170.2 and about combustibility under the NCC external wall requirements. A panel that is also structure, which is where precast concrete often sits, picks up a second set of obligations entirely.
The panel materials in use
- Cementitious: glass fibre reinforced concrete, ultra high performance concrete, fibre cement, architectural precast
- Polymer composite: fibre reinforced polymer in its glass, carbon and phenolic variants
- Metal: aluminium composite panel, solid aluminium, zinc, copper, weathering steel, perforated and folded sheet
- Mineral and fired: terracotta, ceramic, natural stone, engineered stone, brick slip
- Glass: spandrel and back-painted glass, generally delivered as part of a curtain wall rather than as separate panels
- Timber and bio-based: charred and modified timber, bamboo composite, restricted by height and construction type in most codes
Interior panels are a separate group. Glass fibre reinforced gypsum is the dominant moulded interior material and is never used externally, because gypsum is not water resistant. If a project needs the same moulded geometry inside and out, the usual answer is GRG inside and GRC or FRP outside, with the mould shared between them.
Choosing between them
Four constraints decide the material, and they are best applied in this order because each one removes options that the next cannot bring back.
First, fire. Establish the construction type and the rise in storeys. If the building is Type A or Type B and you want a Deemed-to-Satisfy route, the external wall must be non-combustible, which removes every polymer composite, every timber product and any metal panel with a combustible core. What remains is GRC, UHPC, fibre cement, terracotta, stone, glass and mineral-cored metal. If a Performance Solution is available on the project and the client will fund a fire engineer, FRP comes back into the set on the strength of a full-scale AS 5113 test.
Second, weight. Take the dead load allowance in the structural brief and compare it with the table above. On a new building with a frame designed around the facade this rarely binds. On recladding it almost always does, because the existing structure was sized for the original skin and often less. A building that carried 30 mm granite can usually carry GRC; a building that carried a rendered lightweight wall usually cannot, and FRP becomes the only moulded option.
Third, geometry. Flat rectangular panels can be made in anything. Single curvature narrows the field. Double curvature, deep relief, sharp arrises and non-repeating units narrow it to the moulded materials, principally GRC and FRP, because they take their shape from a mould rather than from cutting or folding stock. Once the geometry is moulded, the cost driver shifts from the panel to the mould, which is why repetition and CNC formwork matter more than panel area.
Fourth, cost and programme. At simple repetitive geometry, precast and fibre cement are usually the cheapest per square metre delivered and installed, and precast has the advantage of local supply almost everywhere. As geometry becomes complex and units stop repeating, the ranking inverts, because a precast mould is heavy and slow to modify while a composite mould is not. Lead time follows the same curve.
Weight is the constraint most projects underestimate
The spread from lightest to heaviest cladding panel is roughly a factor of a hundred, larger than the spread in any other facade property, and it propagates well beyond the facade: panel weight sets the crane class, the lifts per day, the size of the cast-in anchors, the local bending in the slab edge and, on a tall building, a measurable share of the foundation load.
Where the panel decision meets the rest of the wall
The panel material also sets the achievable panel size, the joint width and whether the joint can be open, the substructure type, the installation tolerance and the surface finish options. A moulded cementitious panel gives exposed aggregate, acid etch and integral colour, with a 15 to 20 mm joint and a tolerance regime that assumes some batch colour variation. A polymer composite gives a gel coat or PVDF finish and far larger single elements, with higher thermal expansion and a joint sized for it.
Deciding the material without checking these downstream consequences is the most common cause of a facade redesign at shop drawing stage. The panel material, the fixing system and the joint design are one decision taken three times.
Standards and references
- NCC 2022 Volume One, Specification 7 and C2D10 (non-combustible building elements); Schedule 1 definitions (check the edition adopted in your jurisdiction)
- AS/NZS 1170.2 Structural design actions, Part 2: Wind actions
- AS 1530.1 (combustibility), AS 5113 (full-scale facade test), AS 5637.1 (group number)
- AS 4284 Testing of building facades (serviceability, structural and water penetration)
- AS 3610 and AS 3600 (precast concrete); GRCA Specification for GRC; PCI MNL-128
- NATSPEC and MasterSpec cladding worksections
Related terms
Questions specifiers ask
What is the difference between cladding panels and facade panels?
In practice the terms overlap. Cladding panel is the broader term and covers everything from a small flat sheet to a moulded unit. Facade panel usually implies a large-format element that forms a recognisable part of the building’s outer face and is engineered as a system with its own substructure and joints.
Which cladding panel is the lightest?
Fibre reinforced polymer, at 5 to 32 kg per square metre depending on thickness and construction, and aluminium composite panel at a similar weight. Both are polymer or polymer-cored, so neither is non-combustible.
Which cladding panels are non-combustible in Australia?
A product is non-combustible only when it has been tested to AS 1530.1 or appears on the NCC list of materials deemed non-combustible without test. In practice that means GRC, UHPC, fibre cement, terracotta, stone, glass and mineral-cored metal, each on the evidence of its own report.
How thick are cladding panels?
From 3 mm for a polymer composite skin or a metal sheet, through 10 to 20 mm for a GRC skin and 30 mm for stone, up to 100 to 200 mm for precast concrete. Overall system depth including substructure and cavity is usually 100 to 300 mm regardless of the panel.
Can cladding panels be replaced individually?
Only if the fixing system was designed for it. Hook-on rail and undercut anchor systems generally allow single panel removal; panels sealed into a continuous joint or bolted from behind through a sealed cavity often do not, and that becomes a maintenance problem in year fifteen.
What governs how large a cladding panel can be?
Transport, crane capacity, the panel material’s stiffness and the fixing layout, in that order. FRP reaches the largest single elements because it is light enough that transport, not the crane, is the binding limit.
Weight limit on one side and a non-combustibility requirement on the other? ShapeShell-RC is our GRC system and ShapeShell-RT our FRP system, both moulded from CNC-cut tooling. Compare ShapeShell materials
Reviewed by Richard Halvorsen, General Manager, ShapeShift Technologies. Last updated September 2026.