As the Grenfell Tower fire demonstrates, getting cladding systems wrong can have disastrous consequences. But, Simon Young asks, how can professionals ensure such systems are safe when even those that are apparently compliant may still be unsound?
It is not surprising that queries about cladding have, over the past few years, consistently topped the list of technical concerns on commercial property transactions. In addition to their fire and life safety implications, these issues have the potential to frustrate deals and affect asset liquidity. Building surveying has always been an incredibly broad and challenging profession. The job requires us to connect our knowledge of design and construction technology with contract practice and risk management; to interpret a building’s history and project it into the future; to understand costs; and to communicate with specialists and appreciate the views of multiple stakeholders. By using all these skills, surveyors should be able to offer clients concise advice with some commercial insight.
Yet cladding and fire safety might be the biggest technical challenge the profession has faced since the dangers of asbestos became publicised, and suitably skilled and experienced building surveyors can play a crucial role in managing investigations and overseeing remedial works. This article therefore discusses the current regulatory framework, the kinds of cladding system that consistently cause concern, the processes that may be adopted to investigate them, and the commercial implications.
Part B and Approved Document B
The functional fire safety requirements are defined in Part B of the Building Regulations, with part B4 stating: ‘The external walls of the building shall adequately resist the spread of fire over the walls’. The most widely used method of demonstrating compliance with Part B is to follow the government recommendations in Approved Document B. However, doing so is not mandatory, and alternative fire engineering approaches may achieve an adequate level of fire safety.
Before December 2018, Building Regulations did not rule out the use of combustible external wall materials in high-rise buildings where upper floors exceed 18m in height; Approved Document B allowed for the submission of evidence that the entire external cladding system had been classified to BR 135 Fire Performance of External Thermal Insulation for Walls of Multistorey Buildings, using data from full-scale fire tests conducted in line with BS 8414. Where combustible materials are identified in existing high-rise cladding systems, an audit trail incorporating a BR 135 assessment – together with evidence that the system was installed correctly, as designed – may provide assurance that the design did align with Approved Document B at the time it was installed.
However, BR 135 assessments do not offer blanket approval for a material or system type. It is not unusual for such assessments to be entirely missing, or for the reports to be based on a generic arrangement of materials that bear little resemblance to those found on site. Although a Building Regulations final certificate should arguably provide the necessary assurance that Part B and other relevant criteria have been satisfied, these certificates are invariably caveated such that they do not provide absolute evidence of regulatory compliance.
Building Regulation 38 states that fire safety information must be provided at project completion or before occupation, so information to support the final certificate should be sought. It is important to remember that the principal objective of Part B and Approved Document B alike is the preservation of human life. While life safety should be a given for any property, asset protection is not; therefore, the Building Regulations and guidance should be viewed as minimum standards rather than an assurance that a fire will not start or spread.
A fire at online grocer Ocado’s automated distribution centre in Andover in February this year stopped it fulfilling up to 65,000 orders a week, and serves as a reminder that fire can have a huge impact on business continuity, reputation and, in this case, share price. It is prudent to consider these implications, and specialist fire engineering can add value when it comes to enhancing existing assets and designing new developments. In December 2018, Building Regulation 7 was expanded in England to restrict the use of combustible materials that fall short of the Euroclass A2-s1, d0 standard in the external walls of buildings with any storey 18m above ground level that contains a dwelling, institution or room for residential purposes. Although this has been widely referred to as a ban, other properties such as commercial premises, hotels, hostels and boarding houses do not fall under its scope, and combustible materials may still be justifiable in such buildings whether they are above or below 18m in height.
Under the Building (Scotland) Amendment Regulations 2019, which came into force on 1 October [tbc], the situation is similar although more robust. The changes apply to both domestic and non-domestic properties and stipulate a ban on combustible materials in wall cladding where buildings have a storey height of more than 11m; that is, 7m lower than in England. Regardless of whether there is a robust audit trail to demonstrate regulatory compliance at the time of construction, the English and Scottish situations force a commercial comparison between buildings with combustible cladding materials and those without. Where combustible materials are present, especially on high-rise residential assets, there could be a potential risk to asset liquidity and reputation.
