By Shannon Conway, Glenbrook Residential Director.
We are in a climate crisis and the construction industry is responsible for 49% of carbon emissions in the UK. 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.
The reason for this were threefold. Firstly, in a world of sustainability declarations and intentions, we want to demonstrate that green principles are at the heart of our developments. Secondly, understanding how our developments perform gives us additional comfort when agreeing carbon reduction targets with planners, and thirdly, ESG is 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. The scheme completed in January 2021, and is our the fourth BTR scheme so therefore demonstrates an evolved Glenbrook product. From inception, well-being and sustainability were at the heart the design and, with our consultants, we endeavoured to deliver on these areas as efficiently as possible, within the development budget.
Engineering, energy and sustainability consultancy Hydrock promised us a forensic whole lifecycle carbon assessment by delving into the ‘real life’ embodied carbon footprint. 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 (LETI) 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 495 kgCO2e/m2 which reflected a 37% reduction in CO2 emissions, relative to standard industry practice, making it compliant with the LETI Design 2020 target for upfront embodied carbon (495 kgCO2e/m2).
This was made possible through a combination of factors. Firstly, a “fabric first” approach to the thermal envelope resulted in a highly insulated and air tight façade.
We did this while also focusing to reduce materials where possible. Reducing the floor slab thickness by a few millimetres saved 291m3 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. This includes increased use of
renewable energy. VOX utilises one roof for PV cells (the other houses a gym, wellness suite, tenant lounge, and rooftop garden with running track) however there would be an additional opportunity to improve through the introduction of air source heat pumps.
Air source heat pumps require 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 the revised Part L of the Building Regulations which are due to come into effect by June 2022.
A greater focus on occupancy behaviour to reduce energy usage and exploring offsetting emissions off-site will also help. We are working with property managers on the schemes we have delivered, exploring the best ways they can help the 2,000 tenants reduce their operational carbon footprint. Whilst we can’t make people change their behaviour, we can try and make it a bit easier.
This includes a soft landing approach to handover with training on heating and hot water systems, and 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.
Over 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 for delivering on their ESG targets and futureproofing their schemes. Its only through a combined effort, through shared values and aspirations, that we can move towards a net zero offering.