Scott Hall Drive housing, Leeds, UK

Leeds City Council has successfully procured 16 new energy-efficient council houses using NEC. Design and construction was let to Willmott Dixon under a £3.8 million NEC3 Engineering and Construction Contract (ECC) Option A (priced contract with activity schedule) in March 2022.

NPS Leeds, which won the NEC 2024 Business of the Year Award, was appointed NEC project manager and supervisor. Despite various challenges and issues encountered on site, the houses were handed over to the agreed revised budget and programme in March 2024. 

Each semi-detached timber-frame home has its own ground-source heat pump and photovoltaic panels, such that carbon dioxide emissions are over 60% below the building regulations target. The scheme was shortlisted for the NEC 2024 Demonstrating Carbon Dioxide Reduction Initiatives Towards Net Zero Award. 

Leeds City Council is an experienced user of ECC Option A for building works. Recent examples include the £39 million Stourton park and ride and the £8 million Newmarket House waste depot. The council has also delivered the entirety of its new-building housing programme from 2015 onwards using NEC.

Meeting sustainability and social value targets targets

Tom Wilson of NPS Leeds says a key part of the NEC-inspired collaboration was delivering the council’s sustainability and social value targets. ‘The new homes had to comply with the employer’s core strategy policy to achieve carbon dioxide reductions of at least 20% below building regulations and provide 10% of the development’s energy requirements from low or zero carbon sources.’

Wilson says energy efficient and environmentally acceptable principles of design and construction were therefore adopted within the project, which resulted in the orientation, layout, and form of construction of the development being optimised to benefit from solar gain and provide maximum fuel efficiency and reduced carbon dioxide emissions.

‘A fabric-first approach was adopted, which required the homes to be highly insulated with an air permeability less than 3m³/h per m² of floor at a pressure of 50 Pa had to be achieved. Ground source heat pumps with weather compensation and zone control were installed to each home along with 2.4 kWp of rooftop photovoltaic panels. Meters allow the council to monitor the amount of on-site renewable energy produced. Every home also has an electric vehicle charging point.’

He says timber frame construction was adopted reduce the amount of masonry required and in turn reduce embodied carbon dioxide emissions. ‘Cellular soakaway drainage was used for over 60% of the development, the lighter weight of which coupled with manual installation reduced the environmental impacts of transportation and installation.’  

Wilson says on completion each home was assessed for energy performance. ‘The predicted annual carbon dioxide emissions were reported as being 61% below the target rate set out within the building regulations, which can be attributed to high thermal efficiency and use of ground source heat pumps and photovoltaics. Equally the requirement for 10% of the development’s energy to be achieved via low or zero carbon dioxide sources was met.’

He adds that social value and community engagement delivered throughout the duration of the project has met all key performance indicators set by the employer and resulted in job creation within the local economy.

Benefits of using NEC

• NEC requirement to act in a ‘spirit of mutual trust and co-operation’ ensured a collaborative approach by the project team from the outset.
• NEC early warning and risk mitigation process helped the project team resolve several challenges during construction in a timely manner to mitigate delays. 
• NEC-inspired collaboration helped the project team deliver on the client’s challenging sustainability and social value targets.