What Is Class A Decking?
Class A decking refers to an external flooring system that has been fire-tested and certified to achieve a Class A rating (or is made entirely from materials deemed non-combustible without requiring testing according to Commission Decision 94/611/EC). This makes it safe and compliant for use on high-rise residential buildings above 11 metres.
The Class A rating is assigned based on how materials react to fire, specifically assessing their potential to contribute to the spread of flames or smoke. To qualify, a decking system must meet the European standard BS EN 13501-1, achieving a Class A classification for combustibility, flame spread, and smoke production.
Both Class A1 and A2 ratings are acceptable for high-rise applications above 11 metres. Under current UK building regulations, external elements of high-rise residential buildings – including balconies – must be constructed using non-combustible materials.
Failure to specify Class A-rated decking can result in penalties. During construction, fire inspectors assess compliance, and if unsuitable materials are identified, remedial action will be required. This can range from minor corrections to extensive replacement, making early specification of compliant materials essential.
How Are Materials Fire-Tested?
Fire performance classifications typically fall into three categories: non-combustible, limited combustibility, and combustible.
In the UK, fire testing historically followed the BS 476 standards (National Class system). However, most construction materials now require classification under the Euroclass system (BS EN 13501-1).
Euroclass testing is rigorous and closely regulated, providing reliable assurance to architects, specifiers, and manufacturers.
Some materials are inherently Class A1 rated and do not require testing. These include:
- Aluminium
- Porcelain
- Concrete
- Natural stone
- Fibre Cement
This applies only if materials remain untreated – coatings, adhesives, or surface modifications may affect their classification.
Why Is Class A Decking Important?
Following updates to UK building regulations in 2018 – introduced after the Grenfell Tower tragedy – the use of combustible materials on high-rise buildings has been heavily restricted. While the ban initially focused on cladding for buildings above 18 metres similar principles apply to external flooring systems used on balconies in buildings above 11 metres.
Class A decking plays a critical role in improving fire safety, helping to protect both lives and property in high-rise environments.
Importantly, specifying non-combustible materials does not limit design flexibility. Modern Class A decking solutions are available in a wide range of finishes, colours, and formats, allowing for visually striking and practical outdoor spaces that are also weather-resistant and durable.
Examples of Class A Decking Materials
A variety of non-combustible materials can be used to create compliant decking systems, including:
- Porcelain – Highly durable, impermeable, and resistant to scratches, staining, fading, mould, and moss. Available in finishes that replicate wood, stone, or concrete.
- Concrete – Ideal for large surface areas and projects prioritising practicality and strength.
- Natural Stone – Offers a timeless, textured aesthetic with a natural appearance.
- Fibre Cement – Provides a wood-like finish while maintaining Class A fire performance.
Class A materials are divided into:
- A1: Fully non-combustible
- A2: Very limited combustibility
Both classifications are permitted for use on buildings of any height.
Class A Decking Systems and Subframes
It is essential to consider the entire decking system not just the surface finish. Subframes, joists, pedestals, and all supporting components must also be non-combustible to achieve full compliance.
A complete Class A system ensures both safety and regulatory approval for high-rise applications.
Conclusion
Class A decking is a critical requirement for modern high-rise construction, ensuring compliance with fire safety regulations while supporting high-quality design.
Systems such as fibre cement or porcelain decking solutions comprising deck boards, joists, pedestals, and accessories, offer a fully non-combustible, compliant approach to external flooring.
Choosing the right system from the outset helps avoid costly remediation, ensures regulatory compliance, and delivers a safe, durable, and visually appealing result.
