Even the most efficient new school contains significant embodied carbon, so refurbishment will almost always be the better route to Net Zero. We explain how to weigh up opportunities for retrofitting, how to make the most of an investment – and how to avoid throwing good money after bad

In terms of both carbon and cost, it’s almost always more economical to retrofit an existing school than demolish it and rebuild from scratch. But there are inevitably limitations on what can be achieved with an existing building, and a point at which you’re just throwing good money (and carbon) after bad. Taking a whole-life approach to both can help to determine whether it’s worth persevering.   

“Instead of just thinking about the capital costs now, it’s thinking about the costs associated with the decisions we’re making over the lifespan of the building,” explains Kat Adair, Senior Associate in the Sustainability team at Ridge. “That can really help bring all those threads together, so we’re looking at carbon and cost in tandem. You’ve also got to look at how much life you will actually get from that building – if you refurbish but it only gets you ten more years, is it really worth it?” 

Weighing up the costs and benefits

This is a point that Ridge Architecture Partner Alice Parker echoes. Retrofitting can mean many different things, on a sliding scale that starts with upgrading a ventilation system, and progresses to replacing windows, adding insulation and a complete M&E replacement. The most extreme strip right back to the structural frame. “Reusing the structure can be really beneficial if it’s still deemed safe,” says Alice. “But it comes down to the value of materials as well. By the time you’ve replaced the external fabric of the building, it may cost almost as much as a brand-new building. You’ll stretch the lifespan of the existing building by 15-20 years, whereas the design life of a new building is 60 years.”  

On the other hand, this does mean that many school buildings are written off too early, she adds. “We shouldn’t be building new every time as a default, we should be making better use of buildings that might only be 15 years old.”  

We shouldn’t be building new every time as a default, we should be making better use of buildings that might only be 15 years old.

Alice works with the Building Surveying team at Ridge to create estate master plans, and categorise buildings according to their future maintenance requirements. “We can give them gradings to say ‘in the next ten years, this building may need a new roof’, or this building has a life expectancy of five or 10 years.” That forward thinking is important, because projects take a long time to plan and fund. “A life expectancy of 10 years sounds great, but if you don’t start that project in four years’ time, you’re not going to hit that end date.” 

Tackling underutilisation

The other benefit to an estate master plan is that it can reveal there’s no need for new construction. “One of the first questions to ask is whether you’re utilising existing buildings to their full capacity,” says Alice. “When we compare the master plan with forecasts for pupil numbers and staffing, we often find that spaces are underutilised or they’re only used for one thing.” 

When we compare the master plan with forecasts for pupil numbers and staffing, we often find that spaces are underutilised or they’re only used for one thing.

A dining room might only be used for one hour each day, she points out. “Schools often say they don’t have enough breakout space, but that’s a massive one that’s not being used. We design new buildings to be really flexible, so that spaces can be used for different things. We should be doing exactly the same in existing campuses.” 

Reducing energy costs without upgrading systems

Ridge teams help schools to reduce energy consumption and improve the school environment without a full-scale system replacement.  

“It’s not about getting to Net Zero Carbon, but reducing your carbon and your bills based on the system you’ve got,” says Pete Langford, a Partner and MEP Cost Manager at Ridge. “You might keep a gas-fired boiler but make it run efficiently as possible.”  

In older buildings, the cumulative effect of many adjustments over time can add up to poor, inefficient or wasteful operation, he says. “Sometimes you find that the settings have been manually overridden, so the heating system is running 24/7, or it’s not reaching the building.” 

In older buildings, the cumulative effect of many adjustments over time can add up to poor, inefficient or wasteful operation, he says. “Sometimes you find that the settings have been manually overridden, so the heating system is running 24/7, or it’s not reaching the building.

His team rectify this by recommissioning systems and improving controls. “There are also things we can do to improve the heat transfer between the water and the radiators, for example. There are additives that reduce the energy input but achieve the same output.”  

For schools struggling to navigate the often confusing, sometimes counterintuitive path towards Net Zero, there are some essential, universal tools. The energy hierarchy provides a logical framework for any new-build or retrofit. Whole-life calculations can help you to understand and balance cost and carbon over the long term, and estate master plans are invaluable for getting the greatest value from current and future assets. But no two schools are identical, and the right solution will be different for each, depending on the site, the existing buildings and how they are used – and of course, the aspirations of teaching staff and students.  

Alice Parker is a Partner in our Architecture team. You can contact Alice on aliceparker@ridge.co.uk

Kat Adair is a Senior Associate in our Sustainability team. You can contact Kat on katadair@ridge.co.uk

Pete Langford is a Partner in our MEP Cost Management team. You can contact Pete on petelangford@ridge.co.uk