COMMENT We are in a climate crisis and the construction industry is responsible for 49% of the UK’s carbon emissions. To understand our role in responding to this, last year at Glenbrook we decided to get all our new BTR schemes assessed by an external carbon consultant.
Since 2016 we have delivered four BTR schemes for institutional funds across Liverpool and Manchester. With another six in the pipeline, we made the decision to start measuring our carbon performance on all new development.
We wanted to demonstrate the green principles in our BTR schemes. Understanding how our developments perform helps us agree carbon reduction targets in future schemes, for example with planners. ESG is also increasingly on the agenda with our funding partners – they want to see a strong track record and commitment to ongoing innovation.
To start, we needed a benchmark. This would allow us to understand our carbon footprint, show us what we were doing right and identify areas for improvement.
Our scheme Vox, a 280-flat scheme built on a disused industrial site in Manchester, was the obvious choice to test our performance. Vox completed in January 2021 and is our fourth BTR scheme – so demonstrates an evolved product. From inception, wellbeing and sustainability were at the heart of the design.
Forensic assessment
Sustainability consultancy Hydrock delivered a forensic whole-lifecycle carbon assessment by delving into the “real life” embodied carbon footprint of the completed scheme. This included examining the extraction, assembly, maintenance, replacement and disposal of the materials and systems that made up the building design.
Hydrock applied the London Energy Transformation Initiative benchmark to measure the carbon footprint of the development and identify areas for carbon reduction.
Vox performed well. The scheme’s embodied carbon equated to 495kgCO2e/m2, reflected a 37% reduction in CO2 emissions relative to standard industry practice, and met the LETI Design 2020 target for upfront embodied carbon.
This was made possible through a combination of factors. Firstly, a “fabric first” approach to the thermal envelope resulted in a highly insulated and airtight façade.
We did this while also focusing on reducing materials where possible. Reducing the floor slab thickness by a few millimetres saved 291 cubic metres of concrete and took 48 concrete trucks off the road. By laying the slabs earlier and allowing them to settle, our contractors reduced the volume of aggregates and materials required.
Steps to net zero
But there is always room for improvement. Hydrock’s report told us a further 24% reduction in whole-life emissions could have been achieved at Vox with further interventions. These include increasing the use of renewable energy. The building has photovoltaic cells on the roof and we are now looking to add air-source heat pumps.
This requires an upfront cost. We are exploring the viability of these systems and expect the technology will start to become more efficient and affordable as we move towards Part L changes of the Building Regulations, which are due to come into effect next June.
A greater focus on occupancy behaviour to reduce energy use and exploring offsetting emissions off-site will also help. We are working with property managers across our portfolio, exploring the best ways they can help our 2,000 tenants reduce their operational carbon footprint.
This includes training on heating and hot water systems, with clear tenant-user guides. We also host feedback meetings with scheme managers once the development is fully occupied to assess the performance of the M&E design and installations. While we can’t make people change their behaviour, we can try to make it a bit easier to do so.
More than 1,000 people work on each of our developments, including consultants, designers, contractors, sub-contractors and scheme managers. We rely on each person doing whatever is possible within the development constraints to deliver the greenest possible solution.
This includes our funding partners, who we expect to have a genuine commitment to future-proofing their schemes. It’s only through this combined effort, through shared values and aspirations, that we can move towards a net-zero offering.
Shannon Conway is residential director at Glenbrook
