Tasked with unlocking the potential of the existing building, our structures specialists undertook deep analysis of the existing frame, enabling the vast majority to be retained. Our design solution for the internal spaces focused on maximising available space for clear, column-free office floors, whilst also increasing available amenity space and accommodating the four new roof terraces. At the top floor level extension, the exposed concrete and steel structure punctuates the space. The fully exposed precast concrete soffits are clean and uncluttered, facilitated by a new underfloor air ventilation system and perimeter trench heating and cooling solution. This can provide free cooling for up to 85% of the year and provides a simple and adaptable low embodied carbon solution for the additional floor.

Our all-electric building services strategy features a Hybrid VRF heating and cooling system with low GWP R32 refrigerant connected to branch controllers that provide flexible, water based on floor heating and cooling circuits feeding fan coil units. Through the use of carefully designed raft ceilings, the office spaces will feature a striking balance of semi-exposed services and structure. In a further boost to efficiency, building controls will utilise Synapsis and Demand Logic platforms to map energy consumption and quickly identify equipment faults or inefficiencies. This real-time analysis ensures equipment operates as designed throughout its entire lifecycle, helping to close the performance gap between design and reality.

Unlocking design potential

Our structural specialists developed a low-carbon structure using 700 tonnes of X-Carb steel, which alone resulted in an estimated saving of 1,500 tonnes of embodied carbon. With the building designed around a highly repetitive and efficient structural grid, the repeating structural forms meant material waste was reduced and opportunities for future reuse were maximised. The geometric precision and exposed steelwork enhance the design to reflect the character of the historic dock sheds, whilst the exposed saw-tooth roof and the elegant steel trusses play a central role in both the building’s performance and its visual identity.

With the striking ground floor reception and café area sitting above the leisure centre’s sports hall, our specialists worked with the architects and fabricators to deliver a series of trusses to span the 24m clear span needed to meet Sports England design standards. These trusses were carefully dimensioned to achieve the symmetry of 45-degree angles whilst also being suitable for delivery to site as a single splice-free member. The resulting exposed steelwork design contributes to the clean, industrial aesthetic of the incredible entrance sequence designed by Conran and Partners.

Above the swimming pool, deeper trusses were detailed to be storey-high so that the top chord of the truss supports the first-floor office and the end of the bottom chord supports the gym space at ground floor level. The simplicity of the exposed structural form was achieved through rigorous attention to detail, seeing the depths of the inclined sawtooth roof beams varied to align perfectly with the primary beams supporting them.

The exposed columns on the dock elevation were detailed as an asymmetric ‘H’ to provide space for the hidden rainwater pipes, while the developed junction of the trusses ensured they enhance the clean lines of the 45-degree angles. In the office spaces, beams were detailed with a visual hierarchy, using slightly shallower secondary beams supported by deeper primary beams. This arrangement created visible lines of support that run down the full length of the office floors.

In a boost to accessibility, the scheme also saw the creation of a new entrance which is designed to accommodate all users and removing the requirement for separate entrances. Our structures design enabled this feature entrance, with our specialists also unlocking the potential of the revised internal spaces.

Unlocking design potential

Climate resilience was high on the agenda, and inspired by this goal, our team provided multidisciplinary support for the scheme. Working alongside C+W O’Brien Architects, this saw our civil engineering specialists incorporate Sustainable Drainage Systems, including the provisions of green roofing, permeable paving, filter drains, green spaces and tree planting, throughout our design solution. Alongside this, storm water runoff is restricted to the greenfield equivalent rate, with attenuation storage provided to temporarily hold excess rainfall during large storms.

With an eye on minimising carbon-intensive waste, our structural design consists of multiple recase elements. This included a concrete frame of hollow core floor slabs, concrete cross walls above first floor level and an in-situ reinforced concrete frame between basement level and first floor level. At ground floor level, the 1,608 sq ft café, reception and shared amenity spaces required an open, spacious and column-free structural solution. As a result, our design included precast cross walls above first floor level designed as deep beams which minimised the need for reinforced concrete transfer beams within the structure, helping to maintain the open-plan layout below.

Due to extensive archaeological features and a high water table, the site required a carefully designed and managed piled foundation solution. To deliver this, a complex de-watering regime was developed and implemented during the basement excavation to avoid the ground water becoming contaminated by the excavation of the made ground.

Our electrical design brings together cutting-edge technology and functionality. A high-tech LED lighting scheme runs throughout the entire building, blending functional, decorative, and emergency lighting. These systems are controlled via DALI protocols and local presence detection, ensuring energy efficiency without compromising user experience. There is full access control coverage throughout the premises with CCTV both internally and externally adding additional security.

Heating and hot water are primarily delivered by two roof-mounted Air Source Heat Pumps (ASHPs), which feed into dedicated buffer vessels. The low-carbon solution handles the majority of the building’s thermal load and when required gas fired boilers and water heaters can supplement the heating and hot water systems. Each bedroom is equipped with individual humidity fans and heating controls, allowing tenants to tailor their environments personally. Communal areas benefit from a roof-mounted Air Handling Unit (AHU) supported by DX refrigerant condensers, providing both heating and cooling.