From office to home

With increasing numbers of office-to-residential conversions, Aisha Farooq examines some of the fire safety pitfalls that this retrofitting can bring.

It would be easy to assume that transforming an abandoned office block into hundreds of residential homes is an efficient and effective way of tackling the ongoing scarcity of housing in the UK. In fact, the government remains firm in encouraging building conversions through its ever-evolving permitted development right (PDR) rules. But although retrofitting offers a reasonable alternative to having to acquire empty land and build brand new, it has led to both questions over the quality of the final homes and to serious concerns for residents if the in-place fire safety measures are not up to scratch.

Solving the housing shortage?

Consider the following two findings: in February 2023, the think tank Centre for Cities revealed that, compared to Europe, the UK had amassed a backlog of 4.3 million unbuilt homes since the 1950s, owing to the country’s “outdated planning laws”. Another report from 2022 by law firm Boodle Hatfield claimed that 1.8 million m² of UK office floorspace – the equivalent of 248 football pitches – had been “taken out of use in the past year”, with London making up the majority of this disused space. One of the primary reasons for this, the law firm said, was a gradual change in working practices and a shift towards hybrid working models over the past decade, further accelerated by the COVID-19 pandemic.

In May 2013, the government introduced the office-to-residential PDR scheme as a temporary measure to make use of unoccupied office blocks to be found across the UK’s major cities. One of the significant elements of PDR is the waiving of planning permission, provided that “prior approval” from the local council has been sought and that, as of 2021, certain criteria have been met. This removal of planning application delays proved extremely popular among building owners, and with the government also declaring it a success, it eventually became a permanent fixture in April 2016.

Through its PDR guidance, the government has paved the way for developers and building owners to carry out conversions, reducing the planning obstacles they might otherwise face. However, the scheme continues to draw industry criticism, owing to the high percentage of poor-quality homes being created. In fact, the government’s own research on the quality of these converted homes concluded that such housing was “more likely to be characterised by worse quality residential environments than housing created under the full planning permission process”.

Key issues found in these retrofits include the high number of flats falling below the Nationally Described Space Standards and the lack of windows, resulting in very little natural light. Private amenity space was also incredibly low. Dr Ben Clifford, Associate Professor at the UCL Bartlett School of Planning, who led the 2020 research on behalf of the Ministry of Housing, Communities, and Local Government (MHCLG), added: “The problems are particularly acute in larger scale conversions, which are seen most frequently through the office-to-residential route… It does not usually lead to the high-quality design and placemaking outcomes which the government profess to aspire to. Permitted development is not the best approach to deliver homes in which people can enjoy a decent quality of life.”

The dire conditions found within some of these new forms of housing has seen them described as slums of the future, with Paul Scott of Croydon Council, where PDR conversions were at their highest, telling the Financial Times in 2018: “It’s totally unreasonable, and unprecedented in all other aspects of planning, to be able to build whatever you want. We are seeing units with no windows… We are seeing hundreds of substandard units in what were already fairly poor quality office buildings. To pretend that this is somehow responding positively to the housing crisis is a farce.”

With pressure mounting, the rules around PDR were finetuned, with the existing rights under Class O giving way to the new Class MA as of 31 July 2021, restricting the number of square metres in which a conversion could take place – a significant change from the original right where no limitation had been enforced.

Even more worryingly however, Lord Nigel Crisp, the sponsor of the Healthy Homes Bill introduced in 2022, stated that the lack of fire safety measures was also a growing concern, as “normal residential fire regulations do not seem to apply” in converted homes. And it is not just private housing affected by cheap retrofits. According to Caroline Brosnan, Senior Associate at Russell Cooke, the substandard quality of overcrowded conversions has also spilt over into social housing: “Sometimes, my vulnerable clients are housed in converted properties. What I’ve found at times is that there is no paperwork in place in terms of a fire risk assessment or other fire safety measures.”

Clients have had serious fire safety concerns about their assured shorthold tenancy (AST) blocks, including one example of residents not being able to hear the fire alarm when it went off. As Caroline explains: “People were paying a lot of money for what was a relatively new block. Yet there were some serious issues in terms of the fire alarm testing regime, and whether everything was in place that should be.”

She adds: “You can come across these issues where owners perhaps haven’t taken into account a particular fire safety measure... You might find that freeholders of multiple blocks will put their focus on those that are over 18 metres [high], which means that the people in the lower blocks are not getting the attention that they should be.”

Case study: PDR conversions and assured shorthold tenancies (ASTs)

One client of Russell Cooke, with two young children, had made a homeless application to the council and was later offered temporary accommodation. While the council uses some of its own housing stock to accommodate people, it will also rent from private landlords, and after making representations, the client was offered a privately owned, converted office property with three bedrooms. However, the EPC was found to be out of date, and the electrical safety check, which was three years old, had raised certain fire risks with no evidence that they had been dealt with. The council were also unable to produce the fire risk assessment for the property.

After raising these issues with them, the property was taken off let: “They realised that it should never have been offered in the first place. It was clear that there was a lot that the landlord needed to do to make it fit [for purpose], so it was easier for them to withdraw the offer,” Caroline explains.

It was quite scary to go through three or four offers in her particular case where there wasn’t the right safety documentation in place. It’s worrying that no one had looked at those documents to see that they were very out of date or had said there was a fire risk. Seemingly, no one was checking that the fire safety issues had been fixed or dealt with.”

Fit for purpose?

Bringing older buildings up to current fire safety guidelines has been a challenge for many developers in recent years, with a large number of high-rise residential buildings needing to undergo extensive remediation work. Office-to-residential conversions are no different and can also succumb to poor fire safety standards if adequate care is not taken. Most offices have been designed to be open plan in style, with wide open spaces, and the most common work required when changing use will be to internal walls, corridors, and doors to partition the floor space into individual residential units. Therefore, it is very possible, if not entirely expected, that premises undergoing such changes will introduce new fire risks as the existing compartmentation, smoke control, sprinkler coverage, and detection systems can all be impacted by this partitioning.

In addition to the change in use aspect, changes to the Building Safety Act and how they apply to buildings going forward also need to be considered. This includes provisions for a second staircase in buildings over 18 metres in height and additional duties for responsible persons, including piecing together the key building information of their premises for the new Building Safety Regulator and providing access information to fire and rescue services.

Making room for safer living conditions

So, what are the key fire safety considerations for office-to-residential conversions? Approved Document B offers some guidance: “[6.5] Where an existing dwellinghouse or other building is converted into flats, a review of the existing construction should be carried out. Retained timber floors may make it difficult to meet the relevant provisions for fire resistance.” ADB also stipulates specific requirements for converted buildings that are up to three storeys in height and those that are four or more storeys.

From an architect’s standpoint, Robin Callister, Creative Director and Architect at Urbanist Architecture, explains that “the primary issue we find is having to deal with the unknown. It’s not possible to be certain of what fire safety elements are already present within a building, especially if it is 40 or 50 years old.

When it comes to redesigning a building to change its purpose, issues could emerge in the existing structure, as it would have been built prior to modern-day fire regulations, rules regarding asbestos, or when the latest legislation was introduced.”

At times, the complexity of the fire safety work needed as a result of converting from office space can lead to a trade-off, as the cost of installing adequate fire safety measures impacts the quality of other aspects of the conversion, such as fixtures and fittings. Those wishing to change offices to residential spaces must also be aware of all the potential fire risks. Common pitfalls of refurbished buildings include structural changes, access for services, and the type of external envelope in place, specifically whether they are in line with regulations and, if not, what the cost would be to make them appropriate.

In addition to ensuring sufficient compartmentation has been introduced, other areas that developers will need to be mindful of include lifts, staircases, and resident access to escape routes, which will have originally been designed for an open space as opposed to individual units, and in the event of a fire will now be more difficult to navigate.

Case study: How to do office-to-residential conversions well

Urbanist Architecture (UA) converted a medium-sized office building (15,000 sq ft) in Swindon’s town centre into 24 modern self-contained flats for its client. Special care and attention were given to ensuring that adequate light was available in all flats, with preference given over the quality of the residences rather than the number of flats installed. Additionally, each apartment was secured by a full heat/smoke alarm and a high-pressure water-mist fire suppression system in the kitchen and living area.

As the company explains, “The main advantage of using this kind of prior approval is not to do with saving time and effort on a full planning application. It’s that you are working with national rules that function mostly on a yes/no basis, with little judgement from the planning officer and no role for local policies.

Once you’ve got your approval and established your right to turn these into homes, it’s worth thinking about whether you can use planning permission to improve the scheme. Although many councils dislike these permitted development rights, it’s their duty to work towards getting the best result for the residents and the community.”

Other considerations need to be made around the horizontal separation of the building to create boxes with windows and doors, the presence of glazing, lightweight floors and stud work, and the risk of flats overheating. Sprinklers and fire suppression systems can also be challenging to retrofit into an existing structure, again highlighting the importance of keeping a record of a building’s lifecycle, where every decision is recorded in an accurate and transparent manner.

The process of retrofitting office space highlights the importance of having a Golden Thread of information throughout a building’s lifetime. Having such information enables developers to keep track of a building’s changes from commercial to residential, particularly after a change in ownership which may well be the case in a retrofit scenario.

Additional considerations around fire safety will also need to be made for mixed-use developments. This is a not-uncommon scenario when changing use from office space, with the ground floor design adapted for retail use, and the upper floors for accommodation. Such buildings bring their own set of fire safety challenges, such as essential information for emergency services on how to gain access to the residences in the event of a fire.

In its guidance to owners of multi-use buildings, the London Fire Brigade warns of the responsibilities of landlords in ensuring that the correct safety measures are in place. Chris Callow, Head of Policy in our Fire Safety Regulations Department says: “Almost on a daily basis our LFB Fire Safety Officers find dangerous conditions in shops that may affect residential accommodation above. These result in us taking legal action and even prohibiting the use of the building.”


The Department for Levelling Up, Housing, and Communities continues its promises for better quality, more affordable housing. In October 2023, the Levelling-Up and Regeneration Act 2023 was given Royal Assent, and Secretary of State Michael Gove announced that although the landmark bill would speed up the planning system, it would also hold developers to account. Additionally, it would “unleash levelling up in left-behind places”. Part of the government’s long-term plan for housing includes further easing of PDR rules to encourage greater regeneration of the UK’s inner cities and thus widening the scope for commercial building conversions.

In the ten years since the scheme was introduced, there has been no downtrend in office-to-residential PDR conversions. As the fire safety of residential blocks of all heights remains a rightly sensitive area of concern and with the government now looking to expand the scope of the scheme yet further, it brings sharp focus onto the responsibilities of those involved in altering office space into homes for people to live in. Without the presence of adequate fire safety in these buildings it will call into question the future of housing quality, and in turn the future of retrofitting.

With special thanks to Caroline Brosnan of Russell Cooke and Robin Callister of Urbanist Architecture.

Fire & Risk Management is the UK’s market leading fire safety journal, published 10 times a year, and is available exclusively to FPA members in digital and print format depending on your requirements. You can find out more about our membership scheme here.

Aisha Farooq is F&RM Deputy Editor at the FPA.