Nick Haughton of Sapphire explores the key fire compliance considerations when specifying balconies for housebuilding projects.
Balconies are a cost-effective way to add square footage to apartments and give residents coveted private outdoor access. Studies have shown that access to outdoor space is highly beneficial for residents’ mental health and overall wellbeing. This makes balconies a selling point to prospective residents as they can provide private outdoor space even in bustling cityscapes, where it’s often lacking.
In recent years, balcony fires and fires in high-rise residential buildings have been at the forefront of many in the industry’s minds. As we collectively try to adjust to building regulation changes, many are left behind. In fact, research shows that just 15 per cent of architects said they had a good understanding of the post-Grenfell regulations. This understanding gap leaves many in the industry concerned about maintaining compliance in their buildings while managing the other demands of a project.
Balconies are included in the combustible cladding ban, and have been the subject of debate as certain components typically used on balconies are now noncompliant. The aim of the Hackitt report was to establish what measures are necessary for systematic change across the industry.
Róisín Ní Chatháin, director of architecture at BPTW, welcomed these changes, saying that: “As an industry this is the time to re-evaluate current procurement methods and create awareness of what needs to change to see that we are designing and building with quality construction and life safety at the fore.”
The aim of the Government is, understandably, to minimise the risk of fire spread to residents. Hayley Moreton, architect at 3D Reid, affirms, “fire safety is very important when specifying.”
Fire safety should be considered throughout the specifying process to not only ensure compliance with current regulations, but the safety and longevity of the project.
As such, there are many points to consider when specifying balconies on high-rise residential buildings. Some of the key ones are listed below.
Laminate glass has been hotly debated, as the interlayer – while only 1.5 mm thick – is combustible, and therefore non-compliant. However, many in the industry view laminate glass as a safer alternative to monolithic glass due to the safety risks in the case of broken panels.
While monolithic glass leaves a void and allows particles to fall from the balcony, the interlayer in laminate glass typically contains the fragments and preserves the barrier until the panel can be replaced.
Waterproofing concrete balconies
Another challenge in maintaining balcony compliance is the waterproofing membranes used on concrete balconies.
While waterproofing is essential on concrete balconies, many face the challenge of sourcing a compliant membrane for use over 18 metres. Other balcony systems drain through the decking, negating the need for waterproofing and effectively bypassing this challenge.
A key consideration in balcony design regarding fire safety is the inclusion of soffits. Soffits not only provide a sleek finish to the balcony structure but also aid in limiting the spread of a balcony fire. Aluminium soffits have been shown in practice to reduce the possibility of rising or falling embers affecting balconies above and below a fire.
Balcony fires often begin as a result of accidents like overturned barbecues or cigarettes landing on combustible furniture. While such accidents can be minimised through education, the regulations require that all necessary precautions be made to limit fire spread at the design stage.
Cavity barrier integrity
Cavity barriers are essential in maintaining the integrity of a building during a fire. When specifying balconies, it is important to take into consideration the penetrations required to secure the balcony, and the impact this has on the cavity barrier.
Lightweight balconies not only reduce the load on the building, they also require fewer connections to achieve and surpass British deflection standards. Fewer connections means fewer penetrations and lower costs for thermal breaks.
The cavity barrier is also essential for fire-stopping, and this should be considered when specifying balconies. It is essential to ensure that the balcony connections do not undermine the integrity of the cavity barrier, and that an appropriate fire-stopping solution is used.
London Housing Design Guide
The London Housing Design Guide was published in 2010 by the Mayor of London, and forms a common set of housing design standards across the whole of London.
The guide requires that all dwellings provide adequate private open space with a minimum of 5 m2 for two people, and an additional square metre per additional occupant. The minimum width and depth for all balconies and private external spaces is 1500 mm.
The guide aims to ensure all London residents benefit from better homes and neighbourhoods to promote happiness and wellbeing.
A comprehensive perspective
As Jayne Booysen, compliance manager at Premier Estates, said: “The fire strategy needs to be considered. It is also important to consider if residents are disabled and how to evacuate. All these end-use considerations need to be taken into account. We then liaise with local authorities to tailor the fire strategy to suit the residents.”
It is essential when specifying to take a comprehensive approach to ensure all necessary precautions are taken when specifying balconies. To guarantee compliance we must consider the use of the balcony from all aspects, where possible safeguarding residents from fire spread and ensuring every reasonable precaution is taken.