Fire Resilience

Balconies, upstands & terraces:

Lisa Stephens, Product Manager – Building Envelope
Lisa Stephens, Product Manager – Building Envelope
December 2, 2022

Achieving fire safety and protection across the whole building exterior

Architects have long known the value of bringing the outside in. It’s well-rooted in science – access to outdoor and green spaces in densely populated urban areas is key to people being well and living healthily. 

High-rise buildings offer a unique ability to use vertical space to provide homes and workspaces for a growing number of city dwellers. These developments increasingly feature outdoor areas like balconies, terraces and upstands to create much-needed and space-conscious access to the natural world.

With this in mind, it’s important that construction professionals – designers, specifiers and contractors – are well-versed in the fire safety regulations for the building exterior and the ways in which they can assess the performance of materials.

Lisa Stephens, Product Manager – Building Envelope, ROCKWOOL UK, discusses fire safety implications for balconies, upstands and terraces, and examines the ways in which contractors and specifiers can achieve the required performance and improve upon it.

Meeting fire regulations for balconies, terraces and upstands

When specifying and installing façade elements such as balconies and upstands in relevant buildings, specifiers and contractors must select materials with a non-combustibility rating of Euroclass A2-s1, d0 or better. Since 2018, the use of combustible products in external elements of relevant buildings over 18m1 has been prohibited under building regulations.

Insulation products which have been fully tested and classified as Euroclass A2-s1, d0, such as ROCKWOOL HARDROCK® UB34 non-combustible upstand board, are becoming key to achieving Building Regulation compliance. These products do not contribute to fire growth nor emit significant toxic smoke or gases, making them a safer option in the event of a fire for those escaping and for emergency services entering the building.

Fire safety is such a vital matter, determining the reaction to fire rating for building materials should be straightforward – but it often isn’t. Therefore it’s important to only specify products with a Euroclass rating of A1 or A2-s1, d0 where non-combustibility is required. Many products that have passed Test 4 of BS EN13501-5 contain claims of non-combustibility – but while BROOF(t4) is an indication of performance in external fire exposure, it doesn’t test how a product will perform in a fully developed fire or one that penetrates from within. Therefore, it is not a sufficient standalone measure of combustibility – more on this in our article on The Economic Impact of Fire.

The role of third-party certifications

A lot of materials meet the required compliance parameters, so how can decision makers differentiate between products and choose a high-quality provider?

With compliance covered, stakeholders will be looking to build in additional value from the design stage. They often have other criteria like durability, thermal efficiency, and especially in busy urban centres, acoustic performance. Specifying the right insulation materials can help to meet these criteria without compromising on fire safety. 

This is where third-party certifications can be useful. Identifying products that are fit for purpose is not always easy, but one thing that can simplify the process is to look for products that are validated by third parties.

Product certifications are independent appraisals and as such, they provide additional certainty for specifiers and installers that a product has undergone rigorous testing and has met performance claims. Certifications are not lifelong – they are often subject to regular checks and audits by experts, so if a business wants to retain its credentials, it needs to maintain the long-term quality of its products. They can also serve as extra proof that a manufacturer is committed to going above and beyond base market expectations. 

Both ROCKWOOL HARDROCK® Multi-Fix (DD) and Multi-Fix Tapered, for example, are certified by the British Board of Agrément (BBA) and have undergone rigorous testing of their durability, thermal and fire performance. With these further indicators of quality, specifiers and contractors can be even more confident of the performance of these products for their intended uses.

Treating flat roofs as the ‘fifth façade’

Building regulations prohibit the use of combustible materials in the external walls of relevant buildings over 18m – but not in the roof. As a result, flat roofs and roof terraces may contain combustible insulation and may be vulnerable to fire hazards. In high-rise buildings, roofs are frequently used for leisure activities or to house electrical equipment such as solar panels.

Despite regulators not mandating non-combustible roof insulation, more and more forward-thinking developers are choosing non-combustible materials for their buildings. They recognise the many advantages of working with such materials from the start – streamlined construction, simplified compliance, and easier navigation of complex design criteria such as zones that require non-combustible insulation.

Whether used as a means of escape or a place of refuge, the roof is paramount for a building’s fire safety strategy. Treating it as the fifth façade is best practice and serves to futureproof buildings and prolong their lifespan.

Learn more

By using third-party certified non-combustible products for all elements of a building, including the roof, developers can more easily meet regulations, streamline the build and save time. But perhaps more importantly, using insulation materials like stone wool can not only enhance the performance of a building but also enrich the lives and comfort of those living and working in it.

Visit the ROCKWOOL Flat Roof resource hub to expand your knowledge or browse available, third-party certified solutions from our product range.


  1.  The ban on combustible cladding is applicable to relevant buildings over 18m as specified in Building Regulation 7 (2). Separate rules apply for buildings in Scotland over 11m.

Article History

Our experts continually review and update our articles when legislation changes or new information becomes available. 

Current version: 1

First published: 2/12/2022