Copthall Leisure Centre

The London Borough of Barnet commissioned the replacement of the Copthall Leisure Centre to provide a modern facility for the community. The new centre includes three swimming pools (a 25m competition pool, a 25m community pool, and a learner pool), a fitness suite, changing facilities, a café, and spectating areas to accommodate 200 spectators. The site is located just off the A1 Great Northern Way in Allianz Park, Barnet.

Externally, Design ID led the design of a new access road, a large car park with SuDS features, pedestrian footways, a bus parking area, and maintenance access routes. The car park and below-ground services were coordinated with an existing Thames Water potable water main. Civil services included internal and external foul and surface water drainage design, hydraulic modelling, detailed pavement design, external levels design, swept path analysis, and earthworks design. The drainage networks were designed to mitigate the risk of heave. Design ID also designed a foul sewer diversion and provided earthworks and drainage design for converting the existing leisure centre into a new rugby pitch after demolition. Extensive consultation and coordination with Statutory Undertakers ensured efficient wastewater discharge from the swimming pools via a backwash attenuation system and flow control.

Design ID was responsible for the structural design, preparation of contract documentation, and ensuring high-quality construction. The building structure is predominantly two storeys with some rooftop plant areas. A braced steel frame was adopted, with horizontal wind girder steel bracing at the roof levels and diaphragm action from the precast first floor transferring the wind loads to the braced bays. Steel lattice trusses span the 35m over the main pool hall, and corrosion protection of the steel trusses and framing in the pool area was of utmost importance due to the high corrosivity category.

The civil and structural designs were developed through RIBA Stages 2-7. Design ID provided all C&S design information for IST members to review and comment on, producing concise RIBA stage reports through to construction. This ensured the client was aware of all C&S design decisions and that the project met the client’s brief. A desk study and site-specific investigation were conducted early in the project to understand the site, constraints, ground conditions, and existing infrastructure. This informed the appropriate S&C concepts for the site, which were developed and coordinated with the design team, incorporating relevant BREEAM requirements and best practices.

Each aspect of the project was modelled to BIM Level 2 using Revit and Navisworks, allowing for effective design coordination and clash avoidance. BIM meetings facilitated the integration of the C&S design with architectural and M&E services aspirations. The BIM models were used to produce material quantities for benchmarking the efficiency of each design and assisted in the delivery of production information. Steel trusses and long-span beams were prefabricated off-site, viewable in 3D for client review and sign-off.

Design ID participated in regular design team meetings, maintaining consistent core personnel and pulling on additional internal resources as required. An exemplar reporting process ensured relevant information on design progress, risks, opportunities, and delivery programs were clearly reported. A project extranet system guaranteed timely information flow and access to current design drawings. The design integrity was maintained through ISO 9001 accreditation.

The building design was developed and delivered in a BIM environment, with collaboration and coordination to BIM Level 2. The BIM model was used for design coordination, clash detection, standardization, scheduling, quantity take-off, construction planning, erection sequencing, and 4D simulations. This maximised the potential for off-site manufacture and informed the main contractor’s procurement and construction program.

The project faced several challenges, including the presence of high plasticity London Clay, which required all ground floor slabs to be suspended with a compressible void former underneath. The foundations and incoming services were carefully detailed, with heave protection specified. Planning constraints on building height resulted in a shallow roof pitch, necessitating a detailed movement and tolerance report to ensure roof levels avoided ponding of rainwater. Achieving milestone dates was critical, as the project was linked to decanting from the existing live leisure centre. Design ID worked closely with the design team and main contractor to develop a realistic program and ensure seamless construction sequencing.