Mosaic East

Working closely with long-standing client Feldberg Capital, Ambit led the renewal of Knollys House and Stephenson House, now collectively known as Mosaic East. The project involved a complex, live-site refurbishment of two landmark 1960s office buildings, delivering significant infrastructure upgrades while the premises remained in daily use. The project focused on improving energy performance, extending the building’s operational life, and contributing to London’s wider carbon reduction and sustainability targets.

Project in Brief:

• Upgraded power infrastructure with 39 scheduled shutdowns, maintaining full functionality for tenants operating 24/7
• Achieved BREEAM Excellent, SKA Gold, and AirScore Gold certifications
• Preserved and improved the original structure, cutting embodied carbon and reaching EPC B
• Replaced outdated ACM cladding and resprayed retained elements to meet fire safety standards
• Introduced new hard and soft landscaping to both entrances

Phased Delivery for an Occupied Site

Delivering significant upgrades without vacating the premises required detailed coordination. All works were staged to avoid disruption, with major service interventions taking place during evenings and weekends.

A particularly technical aspect was the electrical overhaul. This included replacing low-voltage (LV) boards, emergency systems, and generator panels, all while ensuring no downtime for essential systems. In total, 39 power outages were managed in collaboration with the building management team, tenants, and UK Power Networks to expand the building’s electrical capacity and ensure future reliability.

The programme also covered structural enhancements, including façade updates, a reconfigured lower ground floor featuring flexible Class E workspace, and a new commercial frontage on Cherry Orchard Road. Air-source heat pumps (ASHPs) were installed to eliminate reliance on gas and optimise long-term efficiency.

Sustainable Goals, Lasting Impact

Mosaic East demonstrates how smart refurbishment strategies can support low-carbon ambitions. By keeping the primary existing structure, the team avoided the high carbon costs of demolition and new build, instead preserving the original fabric and minimising waste.

Alongside environmental measures, the project also created a platform for community engagement. It has hosted the Croydon Careers Fair twice in partnership with Croydon Council, BID, and Croydon College, welcoming sixth-form students and introducing them to opportunities in construction and engineering.