The approach to delivering healthy and sustainable buildings has undergone a seismic shift over the past 20 years. And the concept of designing for the future has adapted to reflect the huge social and environmental changes in our cities, homes and communities. Now more than ever, we have become acutely aware of our ingrained responsibility as engineers to create intelligent and low-carbon structures, and to achieve net zero carbon by 2050 we need buildings which are capable of changing use, and can lead long, adventurous lives without a cost on the environment. If the most sustainable building is one that already exists, then we need to question how our new generation of buildings will function in 20 or 30 years’ time and embed sustainable principles into projects from the outset. To deliver truly sustainable structures, we need to demystify the process of reducing carbon, and adopt an informed process driven by research, reflection and evaluation.

Central to this is Long Life Loose Fit which provides a number of key principles. When first introduced in the early 70s the concept of flexible design centred around demountable, lightweight and low energy structures. With buildings changing use more frequently, the emphasis is now often placed on reducing destructive, high-carbon activities such as recoring. To optimise the carbon cost associated with recoring we’ve developed a ‘Soft Core’ philosophy which runs through a number of our retrofit projects. Soft Core repositions the stability elements of an existing core, which are often aggressive to demolish, and places them into the architecture of the façade where they become much more efficient. Through transforming the central core, the building is better able to flex, move and grow to suit each change of use. As well as better buildings, the shared benefits of a Long Life Loose Fit approach mean fewer new build developments and less aggressive redevelopments, transforming our cities and public spaces with healthier buildings, less construction traffic and cleaner air. 

The benefits of adaptable structures should also be recognised through our building awards. Instead of awarding a project the year it completes, it should be assessed 10 or 20 years down the line. A lifetime achievement award which questions how adaptable a building has been and considers its post occupancy performance could largely help to underpin the value of flexible building stock. 

To drive meaningful change our carbon counting methods should also be questioned. As an industry we have only just begun to measure embodied carbon in a small proportion of the building process. To truly measure the carbon within a building, we need to apply a holistic approach, measuring everything from transport and temporary works to retention schemes and post occupancy evaluation. At HTS this is a fundamental aspect of our approach and one we have come to refer to as Total Engineering. By having one team design all the key elements from the existing building, the carbon cost can be consistently measured, benchmarked and lowered at every stage. The recently completed Standard, designed with Orms Architects, exemplifies the substantial benefits of our Total Engineering approach. Working closely with the contractor, we designed both temporary and permanent works as a single integrated system which used smart phasing to minimise the temporary works and its hidden embodied carbon while maximising program advantages. 94% of the primary structure was retained, saving 6,000 tonnes [1] of co2 and resulting in an overall embodied carbon value of 121 kgco2/m2 for the building structure, well below the LETI 2030 carbon target of 201 kgco2e/m2 and the RIBA 2030 carbon target of 144 kgco2e/m2.

[1] Embodied carbon of the retained portion of the structure if it were demolished and rebuilt today 

The Standard construction © Heyne Tillett Steel