hylo
More than Doubled NIA and Rapid Planning Consent in Challenging London Borough
Rapid Planning Success
Through early and strategic engagement with local politicians, Steve identified that the key priority for the London Borough of Islington was the delivery of genuine affordable housing. By slightly exceeding affordable housing targets and crafting a compelling planning narrative that justified the extension of an already tall building, Steve secured both political and officer support for a bold 15-storey extension to the existing tower. This ambitious plan was approved within just 18 months of acquisition, a remarkable achievement in Islington, a notoriously challenging borough for planning approvals.
Doubling NIA
With his in-depth knowledge of building types from projects such as South Bank Tower, Steve recognised the 1960s Seifert-designed tower, originally built for De La Rue currency printing presses had structural redundancy. This insight was confirmed by structural engineers AKTII, who predicted that several additional floors could be added as part of an ‘extend and refurb’ strategy. The result was the addition of 15 storeys to the tower and 3 storeys to the podium, boosting the Net Internal Area (NIA) to 311,000 sq ft, an uplift of 161,000 sq ft from the original 150,000 sq ft.
Delivering Best Product
Steve worked with a mix of city and city fringe agents to develop a commercial brief that offered a blend of large podium floors and smaller tower floorplates, complemented by extensive tenant amenities. These included roof terraces, occupier lounges, bookable meeting facilities, large reception areas, and retail spaces. This design was tailored to appeal to tech-sector occupiers from Old Street, as well as city-based businesses aiming to attract younger talent. Supported by an effective branding and marketing campaign, the scheme has won multiple awards.
Design & Procurement Efficiencies
To optimise space and reduce costs, double-decker lifts and high-level HVAC systems (with no central ventilation plant) were incorporated, achieving significant core efficiencies. Risk allocation was carefully managed, and costs and timelines were controlled through strategic procurement. The initial demolition and structural works (£25m) were awarded directly to a tier 3 contractor, who completed the most complex and risky elements within a contained package. A main contractor (Mace) oversaw the enabling works and subsequently took on a design-and-build lump sum contract once the risks were mitigated.
Detailed Design and Open-Book Procurement
The detailed design and open-book procurement were finalised during the enabling works phase, saving time and ensuring that the product was fully defined before the main contract began.
Cost Savings
By retaining the original structural frame and foundations, and working with the existing building, significant cost savings were realised. This resulted in a sub-£300 per sq ft GIA overall cost.
Calculated Risk Transfer
The initial demolition and structural package covered all core alterations, substructure work, and the creation of a new core and frame. While the scope may have appeared risky, the potential for cost escalation was minimal (estimated at around 10% of a £25m package), allowing the employer to take calculated risks early in the project without committing to the full-scale financial exposure of the overall scheme.
Optimised Programme
By retaining the superstructure and foundations, combined with overlapping detailed design and enabling works, the programme was shortened by at least 18 months compared to a traditional demolish-and-rebuild approach..
Environmental, Social, and Governance (ESG)
Reusing the existing frame saved over 17,800 tonnes of CO2e, contributing significantly to the sustainability of the project.
Amenities
The development’s focus on amenities such as a large frictionless reception area, occupier’s lounge, function suite, bookable meeting rooms, extensive roof terraces, retail spaces, cycle storage, and end-of-journey facilities was groundbreaking when HYLO was conceived. These features have proven invaluable in attracting tenants and are frequently cited as key factors in their leasing decisions.
Relevance to Tenants
The design of HYLO, with a mix of large podium floors and smaller tower floors, has maximised appeal to both prospective and current tenants, offering flexible spaces that can be tailored to meet their needs. Extensive Cat B fit-outs were also completed by the developer, ensuring tenants could quickly occupy their spaces, while simultaneously enhancing value for the owner.
- Other case studies led by Steve Riddell
