Tackle over-design to build more sustainably and cost effectively

Andrew Henderson, executive director, buildings – UK at Ramboll.

The UK needs to build 300,000 homes every year to address the growing UK housing crisis, but in doing so the construction sector needs to find ways to build all new structures more sustainably, says Andrew Henderson

Currently, buildings are responsible for more than 40% of global energy usage and as much as one third of greenhouse gas emissions. The case for change is compelling. The Committee on Climate Change recently set out recommendations for a zero carbon UK by 2050, we have an impending ban on new homes connecting to the gas grid from 2025 and productivity and skills challenges make it an ideal point at which to push for industry transformation and innovation. 

At Ramboll, we recently conducted some of our own research and analysis, which found that on new build office schemes in London alone, we could conservatively save 23,000 tonnes of CO2 every year and £70m in capital expenditure by changing the way we design. In the industry’s efforts to achieve technical compliance and adhere to current codes and guidance, building systems are being designed with approximately 50% more electrical capacity and 30% more heating and cooling capacity than is ever needed! And of course, the space required for all this unnecessary plant that will never run will exist for the lifetime of the building, and never be monetised.

Over-design is wasting capital investment for building owners and driving higher energy consumption for building occupiers. The reality is that nobody wins. It’s bad for business, bad for people, and bad for our planet. It’s clear our industry needs to do things differently. Driving this over-capacity in our building systems is the significant gap between predicted performance and reality. Normally, designers look to buildings codes, occupancy levels and the extremes in environmental conditions to inform design. But this is causing significant waste and inefficiency in plant operation. 

Key to addressing this is data driven design that leads to leaner buildings with better outcomes. Easy to say, but very few are putting this into action. To deliver efficient design we need to really understand how a building will perform, by simulating its operation early in the design development and allowing more informed decisions to be made, and in doing so, deliver leaner buildings.

Whilst building owners and developers might make some savings on initial design fees and take comfort in having a building ‘designed to the codes’, they get a sub-optimal outcome for tenants, users of the building, the environment and, of course, for themselves. 

This challenge of over-design isn’t limited to buildings systems, the same holds true for structures. We’re participating in a really interesting initiative, led by the University of Cambridge, seeking to improve material efficiency across the construction industry. So far, our research has demonstrated that design loading in offices may be more than double the loading that the building will ever experience in its lifetime. 

We have the tools, the know-how and, more importantly, the data to address these challenges. We can turn design on its head and enjoy the fruits of more economical, sustainable, safe, comfortable and compliant buildings.

Andrew Henderson is executive director, buildings – UK at Ramboll.