The first thing to say is that the new building is working brilliantly for our client, Norwich University of the Arts (NUA), and it looks as stunning now as it did at the opening ceremony. The eight-storey building, which occupies an important riverside plot, is an elegant addition to the fine city of Norwich.

But we mustn’t simply bask in the glory of a job well done. After more than a full year in service, it is important that we reflect on the data that tells us how well the building is performing in-use. We now know that the building is using over 90,000kWh of gas and 340,000kWh of electricity per year. This equates to a little over 100kWh/m2/year - slightly better than a typical building of its size but well short of the 2025 and 2030 RIBA targets for operational energy (75 and 55kWh/m2/year respectively). Applying current carbon factors tells us that the annual energy usage equates to around 66 tonnes of carbon dioxide. Whilst the building contains many sustainable features, including a green-roof, heat-recovery ventilation, air-source heat pumps and natural ventilation amongst other things, we know that there are other solutions, such as photovoltaic panels, that could further drive down the building’s energy requirements.

Design work started on the project back in 2017, in what feels almost like a different era. So what might we do differently now, given the chance? The first thing to reflect on is the existing building that occupied the site. Nowadays we tend to advocate, wherever possible, for retaining existing buildings, or at least retaining the primary structure which invariably contains a significant amount of embodied carbon. The existing building was a 1970s block of student accommodation comprising 100 bedrooms, around the same number of bedrooms as the new building.

Could we have retained the old building and refurbished them to modern standards? Perhaps. But against that, this was a dilapidated structure with a condemned basement carpark; the building was poorly arranged on the site; and it was very tight to the River Wensum with a hugely underwhelming street presence. In addition, NUA bought the site with the intention of providing, not only student accommodation, but also much needed teaching and studio space, including a 300-seat lecture theatre. Such a brief could not have been accommodated within the existing structure. NUA have a proud tradition of re-purposing existing city-centre buildings, but this project called for their first new-build. The new building contains a number of high-carbon materials including concrete, steel, brick, aluminium and glass. Could low-carbon alternatives have been used instead? In some cases it is possible they could. It’s worth drilling down into this a little. The building contains a lot of concrete (about 485 cm) - it’s used in the piles, foundations, floor slabs and the retaining walls of the basement. This amount of concrete comes with a heavy carbon price tag but it’s hard to know how much of it could have been avoided - especially in the sub-structure. Concrete with a lower carbon content (using cement alternatives such as GGBS) could perhaps have been used but at a significant cost. Easier savings might have been achievable in the floor slabs - instead of concrete (poured onto a steel deck) we could have considered cross-laminated timber (CLT), a relatively new strategy that is increasingly being employed. If we were designing such a project today, we would work with the structural engineer to produce a carbon report to analyse the structural design and look at options for optimising structural efficiencies. The lower levels of the building utilise a conventional steel super-structure. We were keen to consider glulam timber but came up against intractable issues. The heavy loads of the eight-storey building, combined with wide spans needed for the large teaching spaces on the lower levels, proved too great. Not long into the design process, the new Regulation 7(2) was introduced following the appalling Grenfell Tower tragedy which banned any combustible materials from being used within the external walls of residential buildings more than 18m high. 

Consequently timber frame was no longer an option for tall buildings in the UK. The resulting steel frame contains more than 200 tonnes of steel with a further 59 tonnes of steel reinforcement within the concrete. The upper levels of the building are formed using a panelised light-gauge steel frame. Although still using carbon-hungry steel, this is a highly efficient building method with far lower volumes of steel than a conventional framed building and significantly reduced site waste. Initial design options looked to clad the building in a light-weight rain-screen cladding but this was vetoed by the council’s conservation officer who insisted on a red brick to meet the requirements of the conservation area. While it looks fantastic, the 170,000 bricks used to clad the building come with a significant carbon price-tag.

 If we are to stay within the UK’s carbon budget then rules for conservation areas may have to be re-thought to allow lower carbon materials to be used. Using our in-house carbon tool we calculate the total embodied carbon to be around 2,485 tonnes - equivalent to the annual footprint of over 200 people in the UK. This gives a square metre rate of 564kgC02e/m2 which is only just shy of the RIBA 2030 target for schools (their nearest relevant category at 540kgC02e/m2) and well below the 2025 target. By that metric we appear to have done extremely well and may well have the highly efficient light-gauge steel frame to thank for the good result. On the other hand, the 2030 target is supposed to be very ambitious and we appear to have got very near to it without embodied carbon having been a priority. This is puzzling and suggests that either the RIBA targets are nowhere near ambitious enough or that our calculations have missed a significant amount of carbon. Embodied carbon is still entirely unregulated in the UK and, while there is a standard assessment procedure (developed by RICS), different tools and building scales and typologies will often produce very different results which makes comparison extremely difficult. Regardless of how well the building performs against the RIBA benchmarks, 2,485 tonnes is a lot of carbon. When added to the operational energy over a standard 60-year building lifespan, this gives a total whole-life carbon footprint for the building of 6,445 tonnes of CO2. It is so important that we do not shy away from these numbers - they are big and they are scary but we know there are ways of significantly reducing them to levels that can then be viably offset to achieve Net Zero. This is the challenge we must all face up to – and we know the university is now measuring its total carbon footprint and is actively taking steps to reduce and mitigate it.

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