Inside The 1.4M SF Office Retrofit The World Is Watching

There’s retrofitting and refurbishing an ageing office building.

And then there’s the Citi Tower in London, a 1.4M SF, £300M project that big corporate occupiers, real estate players, financial regulators and environmentalists across the world are keeping a close eye on. 

Citigroup paid £1.2B for its Europe, Middle East and Africa headquarters in the Canary Wharf district of London in 2019. The 2001-vintage building was in need of an overhaul to make it more environmentally sustainable and appealing to staff. 

Rather than knock down the 42-storey tower and build a new one, Citi decided on a retrofit to save 100,000 tonnes of embodied carbon from new construction materials, according to its project announcement in January 2022. 

But once that decision was made, the hard work began. And the project's size, cost and complexity have made it a bellwether for how to retrofit offices, a top Citi executive said at Bisnow's UK Office Series: Leasing Trends and Occupier Demands event.

“We heard from one of our large asset management clients that there are about 2,500 30-storey-plus towers that are coming up for redevelopment in the next five years,” Citigroup Managing Director and Head of International Real Estate Services Kathryn Thomas said last week at The Gilbert on Finsbury Square. “We feel an obligation to show that this can be done.”

In conversation with Overbury Managing Director Chris Booth, Thomas offered a deep dive into the specifics of the project, including the huge overhaul of building systems to create a more sustainable office, changes to internal configurations to help teams work together more efficiently, and how Citi adapted when changes didn’t work.

Overbury is the exclusive fit-out specialist on the scheme, part of a project team that also includes architects WilkinsonEyre and TP Bennett.

“It's 1.4M SF of an existing tower that we've completely stripped back down to its bare bones and are building back again,” Thomas said of the project.

That process involved reglazing large swathes of the building. Three small sections of the tower alone saw 20 tennis courts’ worth of new glazing added. Citi used materials from the same firm that originally glazed the building because the quality was good the first time around and for consistency with the original design. 

The entire heating and ventilation cable system has also been relaid, as has the  low-voltage electrical cable system. All of the building’s air-conditioning systems were repositioned to make them more efficient, Thomas said, meaning 1,200 metres of chiller pipework had to be removed and replaced, all while pipework is in high demand due to the boom in data centre construction and natural gas exploration. 

Citi punched through floors in the middle of the building and connected them with internal staircases to create “villages” within the building, typically of three floors. The concept is intended to allow divisions and teams to cluster together, fostering better collaboration and necessitating the addition of more than 100 flights of stairs, all made from recycled steel. 

The company is aiming for the building to become net-zero in operation and rated BREEAM Outstanding and WELL and LEED Platinum, part of the bank’s overall commitment to net-zero in its own operations by 2030. Its goals also include offsetting the embodied carbon emitted from the retrofitting process, an enormously complicated undertaking. 

Citi has a team of 40 people tracking everything that has left the building as part of the project, from mechanical equipment to building materials to office furniture. It determines whether the materials go back into the supply chain, are recycled or go to landfill. In the latter case, an offset needs to be found, though there is no clearly defined, preexisting way of measuring how much carbon needs to be offset in these situations.

The company is having to devise solutions as it goes. And getting it right has important ramifications in a world where greenwashing worries are rising up the agenda.

“The industry is looking at us,” Thomas said. “Being a bank, we're under huge scrutiny from the regulators, who are really looking at green credentials and statements from organisations, particularly when those statements lead to clients either deciding to invest or not with us. So we have to be incredibly transparent and audit-worthy, and that's a large part of what we're doing.”

As part of the retrofit, Citi has recycled more than 27,000 pieces of furniture, providing them to charities in the UK and Africa, and monitored the disposal of 17,000 tonnes of waste. 

Citi and its project teams began working on the scheme after the purchase in late 2019 and were forced to confront the impact of the pandemic and the shift to hybrid work just months later. The bank now has a policy mandating three days a week in the office, and Thomas said the vast majority of its staff is doing that or more. 

The retrofit has also had to account for Citi’s London headcount almost doubling since the project was first conceived and for technology rapidly changing the way financial services firms work, Thomas said. Citi employs about 11,500 people in London. During the project, staff have been working in a nearby office, and employees are set to return in phases starting next year. 

Despite some unexpected wrinkles, the original design of the project has remained largely intact, Thomas said. That includes uniting floors to create the team villages and changing layouts to bring more meeting rooms and breakout areas to spaces that once housed only desks and offices.

Areas where workers can take time out to rest and rejuvenate during the day will be scattered throughout the building. These areas will include lighting to assist neurodivergent staff and facilities for returning mothers. 

Citi is also making major interventions at the base, centre and top of the tower. The base features larger atria, while the centre features a three-storey-high “winter garden,” wellness facilities such as gyms and medical facilities, and a restaurant. The top of the tower, where client meetings will happen, will also feature internal gardens. 

While Citi's overall thesis has remained intact, a project of this size inevitably requires change. Booth pointed to Citi's agility, including the redesign of more than 20 floors just last year, and Thomas highlighted that the company had shelved plans to use some furniture. While the furniture was flexible and adaptable, it didn’t allow the sightlines and space configuration team members needed in a fast-paced financial environment. 

“We trialed it at scale with hundreds of users and found out in time to be able to course-correct and really re-lay out the floors how we knew it would then work going forward, without disturbing the program,” she said.