Fibre Reinforced Facade Encyclopedia: Materials
FRP facade panels are exterior cladding elements laminated from glass fibre and a cured thermoset resin, produced as a 3 to 8 mm single skin, as a monocoque shell 10 to 50 mm deep, or as a sandwich with a foam or honeycomb core. In service they weigh 5 to 32 kg per square metre, roughly a tenth of precast concrete. The material itself is covered on the fibre reinforced polymer page; this page is about the panel: how it is built up, how large it can be, how it is fixed, how it moves, and which compliance pathway it takes on an external wall.
Stiffness, not strength, sizes an FRP panel. The laminate has an elastic modulus of 10 to 25 GPa against 30 GPa or more for concrete, so almost every architectural panel is governed by a deflection limit and gains its stiffness from shape rather than from thickness.
At a glance
| Property | Typical value | Note |
|---|---|---|
| Single skin thickness | 3 to 8 mm | ShapeShell-RT published range |
| Monocoque depth | 10 to 50 mm overall | Returns, ribs and curvature provide the stiffness |
| Weight in service | 5 to 32 kg/m² | ShapeShell-RT published range |
| Largest single element | 2.4 by 10 m | ShapeShell-RT published maximum |
| Flexural strength | 150 to 250 MPa | ShapeShell-RT published 221 to 241 MPa |
| Elastic modulus | 10 to 25 GPa | Deflection, not strength, governs panel design |
| Thermal expansion | 15 to 30 x 10⁻⁶ per °C | Higher than concrete; joints and slotted fixings absorb it |
| Joint width | typically 12 to 25 mm | Calculated from panel length and the movement coefficient |
| Surface system | Gel coat or PVDF paint | Part of the specification; the resin alone is not UV stable |
| Fire | Reaction-to-fire plus full-scale facade test; never non-combustible | ShapeShell-RT: AS 5637 Group 1 (AWTA); EN 13501-1 B-s2; AS 5113 and BS 8414 pass at BRE Global |
How the panel is built up
A facade panel is a laminate schedule, not a single material. Working outward from the mould face: a pigmented gel coat forms the weather surface and carries the colour and gloss; a fine surface tissue keeps the fibre pattern from printing through; chopped strand mat builds thickness and conforms to curvature; and directional fabric, woven roving or stitched biaxial, is added where the panel has to span. Ribs, edge returns and bonded-in stiffeners are laminated in the same operation.
Hand lay-up suits one-off and low repetition geometry and is the mainstay of architectural work. Vacuum infusion draws resin through dry fibre under vacuum, raising fibre volume fraction to 40 to 60 percent and producing a denser, more consistent laminate with lower void content. Both are moulded processes, so the tooling defines the face and CNC-cut moulds make complex geometry economical.
Panel size, span and stiffness
FRP reaches panel sizes no cementitious cladding can. Single elements are produced up to 2.4 by 10 metres, which removes joints from an elevation and lets a single panel wrap a corner or run a full storey height. The limits are the mould, the transport envelope and the demoulding geometry rather than the weight.
The stiffness comes from form. A flat 4 mm laminate is a floppy sheet; the same laminate folded into a tray with 60 mm returns, or moulded with a single curvature, becomes a structural element. That is why FRP panels are designed as shells and why deep profiles cost little more than shallow ones. Deflection limits on cladding are commonly taken as span over 180 to span over 240 under serviceability wind pressure from AS/NZS 1170.2, and the limit should be agreed with the facade engineer at design stage rather than assumed, because it usually sets the panel geometry.
Fixings and support
Panels are hung from stainless steel or aluminium brackets fixed to a substructure of rails or directly to the structure. The connection into the panel is made through laminated-in inserts, bonded backing plates or a thickened laminate boss, all of which spread the point load over enough area that the thin skin is not punched through. Resin and glass creep under sustained load, so a fixing that relies on clamping a plain laminate between washers is a poor detail; the load path should go into a designed insert.
Because the panel expands and contracts more than its supports, only one point per panel is fixed rigidly and the remainder are slotted or oversized to allow movement. Fixing centres are set by the deflection limit rather than by strength, and every fixing is designed for wind suction, which is usually the governing case on a lightweight cladding: a panel at 10 kg per square metre has almost no self weight to resist uplift.
Movement, joints and water
The thermal expansion coefficient of 15 to 30 x 10⁻⁶ per °C is the number that drives joint design. A 10 metre panel on a dark elevation can see a surface temperature swing well above the air temperature range, and the resulting movement has to be accommodated in joints of typically 12 to 25 mm rather than in the fixings.
Open drained joints over a ventilated cavity suit FRP well: the panels are a rainscreen, the cavity drains and vents, and the waterproofing is the membrane and flashings behind rather than a sealant line that has to move 20 mm. Where sealed joints are used, the sealant must be movement rated for the calculated joint travel and compatible with the gel coat, and it must remain accessible for replacement within the panel’s life. Cavity barriers are part of the external wall and are designed with the panel layout, not added later.
Fire and compliance in Australia
FRP is a polymer composite. It cannot pass the AS 1530.1 furnace test, it is not non-combustible, and it is therefore outside the Deemed-to-Satisfy provisions for external walls of Type A and Type B buildings under NCC 2022 Volume One (check the edition adopted in your jurisdiction). This is the first thing to establish on any project, because the pathway affects programme, cost and the consultant team.
The route that is available is a Performance Solution under Verification Method C1V3, supported by a full-scale facade fire test and a fire engineer’s assessment of the specific building including its sprinkler protection, cavity barriers and evacuation strategy. ShapeShell-RT passed the full-scale BS 8414 and AS 5113 facade test at BRE Global, meeting all AS 5113 criteria; it holds an AS 5637 Group 1 classification from AWTA Product Testing and an EN 13501-1 classification of B-s2. Those results are evidence for the assessment; they are not a substitute for it.
Handling, transport and installation
Light panels are easy to lift and hard to hold. A 10 square metre panel at 15 kg per square metre weighs 150 kg, which two or three people can place, but the same panel behaves like a sail in wind, so installation windows are set by wind speed rather than by crane capacity. Large elements are handled on a spreader frame at the laminated-in lifting points shown on the shop drawings.
Surfaces are protected until the scaffold comes down; gel coat is durable but not immune to abrasion from stillages, straps and site traffic, and a repaired gel coat rarely matches an original one on a gloss face. Panels are stored on edge in stillages, supported at the designed points, and are never stacked flat unsupported, because a thin laminate takes a set under sustained load.
Standards and references
- ASTM D790 and ISO 14125 (flexural), ASTM D638 and ISO 527 (tensile), ASTM D2584 (fibre content)
- AS 5113 (full-scale facade test), BS 8414 with BR 135, NFPA 285
- AS 5637.1 (group number), AS 1530.3, EN 13501-1, ASTM E84
- NCC 2022 Volume One C2D10, C1V3 and Specification 7
- IBC Section 2612 / 2613, Fiber-reinforced polymer
- AS/NZS 1170.2 (wind actions) and AS 4284 (building facade testing)
Where this matters on a ShapeShift project
Spanda, Elizabeth Quay, Perth: A large freestanding sculptural work built from moulded composite shell elements, using the same laminating and panel logic as facade work. It shows why this class of material is chosen for this class of geometry: double curvature at scale, with self weight and wind load governing.
Related terms
Questions specifiers ask
How big can an FRP facade panel be?
ShapeShell-RT panels are produced up to 2.4 by 10 metres as a single element. Larger areas are made as monocoque or sandwich elements and joined on site. The practical limits are the mould, the transport envelope and demoulding, not the weight.
How much do FRP facade panels weigh?
Between 5 and 32 kg per square metre depending on thickness and construction, against 30 to 50 for glass fibre reinforced concrete and around 360 for a 150 mm precast panel.
Are FRP facade panels non-combustible?
No. FRP has a polymer matrix and cannot pass a combustibility test. On external walls it is used as a Performance Solution supported by a full-scale test. ShapeShell-RT passed the full-scale BS 8414 and AS 5113 test at BRE Global and holds an AS 5637 Group 1 classification from AWTA Product Testing.
What governs the design of an FRP panel?
Deflection. The laminate modulus is low, so panels are sized to a deflection limit under serviceability wind pressure, commonly span over 180 to span over 240, and they gain stiffness from returns, ribs and curvature rather than from thickness.
How are FRP panels fixed?
Through laminated-in inserts, bonded backing plates or thickened laminate bosses connected to stainless or aluminium brackets. One fixing per panel is rigid and the rest are slotted to allow thermal movement, and every fixing is designed for wind suction because the panels have very little self weight.
Do FRP panels fade?
The resin is UV sensitive, so the surface system does the work. A pigmented gel coat or a PVDF paint finish gives 50 years or more of service, and the coating specification and warranty should be reviewed alongside the laminate.
Designing a facade panel that is too large, too curved or too light for concrete? ShapeShell-RT is our FRP system, 5 to 32 kg per square metre, with a full-scale AS 5113 and BS 8414 pass at BRE Global. See ShapeShell-RT specifications
Reviewed by Richard Halvorsen, General Manager, ShapeShift Technologies. Last updated September 2026.