Designing balconies, terraces, podium decks and flat roofs now requires far greater scrutiny of fire performance, material classification and long-term durability than ever before. Regulations governing the external envelope have tightened significantly, particularly for high rise and higher risk buildings, and scrutiny now extends beyond the primary structure to include specified attachments such as balconies.

Under the Building Safety Act, fire safety requirements for Higher Risk Buildings have been strengthened. In England, Wales and Northern Ireland, the statutory trigger height for combustible material restrictions has been 18 metres and is moving towards 11 metres. In Scotland, the statutory trigger is already 11 metres. Even where 11 metres is not yet a statutory trigger in England, it remains highly relevant under Approved Document B, which continues to influence specification decisions. Regulations are under ongoing review and subject to change, so early engagement and careful specification are essential.

Balconies are classed as specified attachments. This means the entire build up can be drawn into the requirement for Class A non-combustible materials. Architects and developers are increasingly future proofing schemes by specifying fully Class A systems below regulated heights, including at low rise and even ground level, to ensure long term compliance and assurance.

Wallbarn provides fully non combustible Class A decking, paving and substructure systems designed specifically for high rise residential, healthcare and public sector buildings, without compromising on design intent or visual quality.

Understanding Class A Classification

Steel, aluminium and ceramic materials are deemed Class A under EC Decision 96 603 EC and classified in accordance with BS EN 13501 1. These materials do not contribute to fire growth.
Wallbarn’s Class A systems are built around these core materials and structured as a complete external flooring and landscaping solution.

Substructure

MetalPad Ex adjustable steel pedestals combined with our extruded aluminium Box Rails or I-Plus Rails form a fully non-combustible Class A substructure platform. Class A rated fixings and connectors ensure continuity of compliance across the entire build up. This robust framework provides the structural foundation for decking, paving and integrated landscaping schemes.

Decking

The substructure supports a broad range of Class A decking finishes, including ExaDeck extruded porcelain boards, CDeck cement fibre boards, and aluminium decking. This breadth of offering enables architects to achieve the desired aesthetic, whether contemporary, natural or industrial in character, while maintaining full regulatory compliance.

Paving

For paving applications, dedicated headpieces and connectors integrate directly with the aluminium rail system, enabling suspended porcelain or slab paving systems on a fully compliant Class A support structure. This allows seamless coordination between paved and decked areas without introducing combustible components.

Planter and Landscaping Integration

The same substructure also forms the basis of the Permeate Planter System, allowing integrated hard and soft landscaping, seating and paving to be installed on a unified, fire rated platform. Designers can create cohesive rooftop and podium environments with consistent detailing and performance across all elements.

By offering compatible decking, paving and planter solutions on one engineered platform, Wallbarn ensures that compliance does not restrict creativity. Projects can meet the highest fire standards while delivering refined finishes and carefully considered external spaces.

The Zintec 200 anti corrosion coating applied to MetalPad Ex pedestals has been independently tested and classified to A2. All components are selected and engineered in line with Approved Document B and BS 8579 guidance for balconies and terraces.

There are no plastic pedestals, no polymer heads and no combustible gaskets introduced into regulated projects. The entire system is genuinely non-combustible.

Structural Performance Beyond Fire Rating

Fire classification alone is not enough. Structural strength, deflection control and long-term durability are critical, particularly in healthcare, public access and high traffic environments.
MetalPad Ex pedestals have been independently weight tested to approximately 49.86kN. When used with the optional Spreader Plate, weight tolerance increases further while also reducing point loading on vulnerable subfloors such as insulation or roofing membranes.
Aluminium joists have been independently tested for deflection at recommended centres. ExaDeck boards have been independently tested and can achieve a load tolerance of 4.41kN at 400mm centres and deliver R11 slip resistance, supporting safe use in wet conditions.

Double rectified ExaDeck boards are manufactured to sit flat and straight on the rails, reducing rocking or movement. Combined with 60mm wide aluminium joists and precision fixings, this creates a stable, secure deck build up suitable for demanding commercial and healthcare schemes, while maintaining clean lines and a premium visual finish.

Ultra Low Threshold Solutions

Refurbishment and retrofit projects often present restricted upstands at door thresholds. Wallbarn offers Fixed Height Class A pedestals designed for ultra-low threshold applications, enabling compliant suspended deck build ups in tight conditions.

These pedestals integrate directly with the aluminium rail system, allowing architects to achieve both fire compliance and level access without compromising structural integrity or the overall look and feel of the finished surface.

M-Tray® Modular Green Roof

For flat roofs and podium decks where Class B roof performance is permitted, Wallbarn’s M-Tray® modular green roof system provides an independently tested BROOF(t4) solution.
Each module is pre grown and delivered ready to install. The trays are removable, allowing access to the subfloor for future maintenance. Sedum and wildflower option is available, and the system is manufactured in the UK.

M-Tray® offers a practical, compliant route to achieving biodiversity and sustainable drainage objectives while maintaining fire performance in accordance with roof classification requirements.

Case Study: King’s College Hospital, London

A recent benchmark scheme demonstrates how fire compliance, structural performance and aesthetics can work together in a highly regulated healthcare environment.

Wallbarn supplied the fully Class A fire rated substructure for a 170 square metre rooftop Critical Care Unit garden at King’s College Hospital in Camberwell, London. The terrace functions as an operational outdoor extension of the hospital’s CCU, allowing vulnerable patients to experience a carefully designed outdoor environment that supports recovery and overall wellbeing while remaining connected to essential medical equipment.

Given the building height and the vulnerability of occupants, fire safety was non negotiable. The system comprised MetalPad Ex steel pedestals with Zintec 200 coating, aluminium rails and Class A rated fixings, supporting a non combustible decking finish that met both regulatory and aesthetic requirements.

The suspended deck build up accommodated complex medical services beneath the surface while allowing future access for maintenance. Delivered on a live hospital site with restricted access and logistics, the project demonstrates Wallbarn’s ability to support technically demanding schemes from early design through to installation.

Learn more about this case study

Technical and Logistical Support

Wallbarn supports architects and contractors at every stage of a project, including NBS Source specifications, BIM objects and CAD details, independent fire and structural test reports, early-stage technical consultation, and on site coordination and delivery support.

As regulations evolve and scrutiny of external materials increases, selecting a fully non-combustible, independently verified system is essential.

Wallbarn provides compliant, structurally robust and aesthetically versatile decking, paving and green roof systems designed for today’s regulatory environment and tomorrow’s expectations.

For technical guidance or project support contact Wallbarn