Iain Cox, Chair of the Business Sprinkler Alliance

The new permitted development right (PDR) allowing additional storeys on homes and residential buildings may well be one panacea to the housing shortage and make it easier to extend existing homes and buildings, but what does this mean in terms of fire? 

Under the new PDR rules, which came into force in August, building owners are now allowed to add up to two storeys on top of existing detached and purpose-built blocks of flats through a fast-track process. The concept may be sound in terms of speeding up the development of new homes without having to find new land to build on, but the devil is in the detail.

Adding two floors to an existing building may seem on paper to be an exciting new opportunity for developers, but it’s not without its challenges. It is a material alteration to a building; therefore stakeholders need to look at the building in its entirety. Additional storeys will create an entirely new building which needs to be looked at from the ground-up. At a fundamental level will the structure take the additional load? Most rooftop extensions are built using prefabricated materials, therefore it’s important to consider the materials being used and their impact. In short, have I changed the risk by adding these two floors?

These changes link to fire safety; principal amongst them is the safety of all residents. You have to consider how people evacuate in the event of fire and also access for firefighters. When you look at the changes made to Grenfell for example, you cannot simply look at the new changes to the building, you have to look at it in its entirety.  How do we keep all people safe in a building that has been changed?

The other consideration is the new 11-metre storey height sprinkler threshold that comes into force on the 26th November will mean that some of these rooftop extensions would fall into that bracket for this sprinkler requirement.  Regardless of this change, from a fire safety perspective sprinklers make a lot of sense and are a key component in the long-term strategy of any building. If considered early in the design process, they can be included and implemented whilst balancing costs. Developers need to have an open mind to other fire safety solutions, particularly sprinklers, and think holistically about the best solutions to employ for such a change.

Often stakeholders do not even consider sprinklers at all – not because of the cost – but simply because it is not mandatory. It is a barrier in people’s minds. With this new permitted development right, people need to think about fire safety and potential solutions.  Don’t dismiss an automatic sprinkler system early in the design process, as it enables the balancing of other fire protection measures, which in-turn opens up a number of significant design opportunities. Embrace these solutions, as it may well mean you have a solution for some of the challenges you might face, whether it is a means of escape or access for firefighters.