The government has predicted its new ban on combustible materials will add significant extra costs for building owners converting office blocks into residential schemes
The policy, announced last week, prohibits combustible materials from the external walls of all new buildings over 18m tall (approximately six storeys) and containing housing.
While the measure will not apply to existing buildings, the Ministry of Housing’s impact assessment of the policy states that office-to-resi conversions will come under the ban.
The overall cost of the combustibles ban for building owners is forecasted at between £249 million and £337 million over the next decade, with office-to-resi schemes coming in at an additional annual cost of £5.9 million.
The ministry estimates that 75 office-to-resi conversions over the 18m limit will be affected by the policy each year.
Levitt Bernstein’s head of housing research, Julia Park, who has raised concerns with the government about office schemes converted under permitted development rights (PDR), welcomed the policy.
‘The risk to life is much greater in buildings that we sleep in,’ she said.
She added that the costs of bringing office blocks up to the new standards would make developers who are ‘only interested in a quick profit think a bit harder’.
Park pointed out that while office buildings were often safer than housing as they were designed for evacuation, the evacuation strategies in commercial buildings are ‘predicated on daytime use and subject to regular fire drills’.
‘I wonder whether anyone has thought about whether the strategy should become “get out” rather than “stay put” when an office building is converted to residential use.
‘Do the residents know what they should do, and what happens to people who need help to escape?’
Laurence Osborn of GRID Architects, the firm behind Vantage Point, the conversion of Archway Tower in north London, welcomed the new policy and said the practice already treated conversions as ‘a new building’.
‘Office-to-resi conversions are complex and often require bespoke solutions to achieve building control compliance and should not be assessed any differently to new-build residential,’ he said.
He added that to achieve full compliance with Building Regulations at Vantage Point, GRID had stripped the office building back to its frame and re-clad the building.
’Too many examples appear to not be as rigorous in their approach,’ he said, ‘leading to poor quality accommodation that on face value appears non-complaint – it is no surprise that office-to-resi has had a negative press recently.
‘If done properly, in the right place and to the right quality, the typology offers a sustainable contribution to meeting housing need.’
RCKa Architects’ Russell Curtis, who has called for the government to embed space standards within Building Regulations, said it was time ministers took a ‘wider view’ of office-to-resi conversions.
‘It’s ironic that the government has suddenly decided that office conversions should also be subject to the same standards as straight-up residential buildings when it comes to life safety, yet as far as quality of life is concerned, it seems entirely uninterested,’ he said.
‘Where was the legislation change when developers started squeezing one-bed flats into 15m²? The hidden cost of such tiny flats might be less immediately catastrophic, but the long-term effects on mental wellbeing and happiness are no less profound.’