Internal Systems That Last: How RC/GRC Supports Durable, Light, Fire-Rated Internal Cladding
The Cladding Challenge in Interior Architecture Internal cladding systems play an essential role in shaping the performance, safety, and atmosphere of a building. While often perceived primarily as a visual finish, cladding must also deliver durability, contribute to fire safety, and integrate seamlessly into modern construction methods. In practice, many traditional materials used for interior cladding—such as plasterboard or standard cement-based boards—pose limitations. They can be heavy, prone to cracking, or difficult to form into complex geometries. In high-traffic environments, they may show wear earlier than expected, adding maintenance burdens. When fire safety standards are applied, some of these conventional solutions fail to deliver long-term confidence. This tension—between aesthetics, performance, and compliance—creates a consistent challenge for architects and building consultants. Reinforced material systems such as RC/GRC (Reinforced Concrete / Glass Fibre Reinforced Concrete) present a compelling alternative. Lightweight, strong, and fire-rated, RC/GRC is increasingly being applied not just to external façades but also to internal cladding systems where longevity, safety, and refined finishes matter most. This article explores how RC/GRC addresses the demand for durable, light, and fire-rated internal cladding within modern architecture. Why the Market Needs Better Internal Cladding In architectural design, internal cladding serves three interconnected purposes: Visual expression – shaping how occupants perceive and experience spaces. Functional performance – protecting structural elements and supporting acoustic, thermal, or fire requirements. Lifecycle value – maintaining integrity and aesthetics without premature repair or replacement. However, relying on traditional materials exposes several shortcomings: Weight and load implications: Standard cement-based panels or thick gypsum solutions often add considerable dead load, complicating structural and installation requirements. Fire performance gaps: Not all commonly used internal finishes are non-combustible or tested to international standards, leaving risks in high-safety environments. Durability issues: Plasterboards and non-reinforced gypsum systems are prone to cracking, moisture absorption, or impact damage. Design restrictions: Complex curvatures or seamless large spans are often unachievable without introducing multiple joints or heavy reinforcement. As a result, architects and consultants are frequently forced into trade-offs—sacrificing either design intent, performance, or cost efficiency. The question is: Can an internal cladding system provide strength, fire resistance, lightness, and aesthetic flexibility—without compromise? Introducing RC/GRC for Internal Cladding RC/GRC represents a class of engineered materials where cementitious matrices are reinforced with glass fibres or other fibres to significantly improve tensile strength, impact resistance, and performance compared to traditional gypsum or cement boards. RC (Reinforced Concrete) in thin-walled form provides exceptional durability and fire resistance while reducing embodied energy. GRC (Glass Fibre Reinforced Concrete, often termed GFRC) enhances tensile and flexural strength, allowing thin sections (as little as 15–25mm) while maintaining structural stability. By introducing fibre reinforcement, RC/GRC achieves: Up to 30% lighter weight than traditional GFRC alternatives. Higher flexural strength (typically around 25 MPa) and compressive strength exceeding 45 MPa. Non-combustibility, meeting AS 1530.1 and ASTM fire classifications. Versatility of form, enabling flat panels, double-curved geometries, domes, and intricate internal finishes. This makes RC/GRC a natural fit for interior applications such as: Wall cladding panels in high-traffic public buildings. Column wraps and ceiling features. Custom feature walls and vaulted ceiling elements. Acoustic panelling with integrated fire safety. Durable surfaces in transit hubs, universities, and civic spaces. Why RC/GRC is Ideal for Internal Systems 1. Lightweight but Strong Despite being cement-based, RC/GRC achieves high strength-to-weight efficiency. With panel thicknesses as low as 12–25mm, internal systems avoid unnecessary structural loads while still delivering resilience. Compared to plasterboard, RC/GRC is significantly stronger, and compared to traditional precast panels, it is substantially lighter. For example, ShapeShell™ RG (Reinforced Gypsum) offers 30% less weight than GFRC while maintaining strength for internal applications. 2. Fire Safety and Compliance Fire resistance is critical in interior applications, particularly in public buildings, transport hubs, and commercial complexes. RC/GRC is inherently non-combustible, with fire testing certifications including: Class A / Group 1 fire rating (ASTM and AS standards). No flame spread, smoke development, or fuel contribution under ASTM E84 testing. This ensures compliance with stringent building codes while providing peace of mind in high-occupancy environments. 3. Durability and Longevity Unlike plasterboard or standard cement sheet, RC/GRC resists: Impact damage in corridors, classrooms, and public spaces. Moisture absorption, reduces the risks of warping, swelling, or mould growth. Cracking, thanks to distributed fibre reinforcement that mitigates brittle failure modes. The result is reduced maintenance and a significantly longer service life, lowering lifecycle costs. 4. Aesthetic and Design Flexibility RC/GRC excels in supporting architectural intent: Smooth off-form finishes directly from moulds. Textured acid-wash or aggregate finishes for tactile variation. Polished or coated surfaces compatible with RAL colour systems, PVDF coatings, or metallic effects. This allows architects to use RC/GRC as both a functional cladding system and a design language, ensuring consistency across project interiors. 5. Ease of Installation RC/GRC panels are designed with engineered mounting systems that allow ±20mm on-site adjustability. Panels can be mechanically fastened to secondary frames using standard drywall techniques. The lightweight nature simplifies handling, reduces crane or hoist requirements, and speeds installation. For high-rise interiors, this provides direct cost and time savings. 6. Sustainability Credentials Sustainability is no longer optional. RC/GRC supports environmental objectives through: Reduced embodied energy compared to traditional concrete. Options for silica-free formulations using recycled glass. Longevity that reduces replacement cycles and waste. By combining green materials with high durability, RC/GRC aligns with modern environmental benchmarks such as Green Star or LEED. Applications in Practice Transport Infrastructure High-traffic transport hubs require materials that resist impact, remain non-combustible, and maintain their finish under constant use. RC/GRC internal cladding panels deliver these qualities while supporting acoustic treatment for public spaces. Educational Buildings Universities and schools benefit from RC/GRC’s impact resistance and fire rating. Internal panels or feature walls retain integrity in demanding environments, reducing long-term maintenance costs. Civic and Cultural Buildings Museums, galleries, and civic centres often demand large spans of visually seamless cladding. RC/GRC enables complex geometries such as domes, vaulted ceilings, and curved walls—without introducing weight penalties. Commercial Interiors Office lobbies and retail environments demand finishes that project durability and refinement. With textured or
