For decades, the UK construction sector has been working hard to reduce the operational carbon of buildings. As we continue to focus on operational CO2 savings, attention has also turned to embodied carbon, the total amount of greenhouse gas emissions released by the manufacture and supply of construction products and materials, as well as the construction process itself. According to the UK Green Buildings Council “depending on building type, by the time a building is occupied, somewhere between 30% and 70% of its lifetime carbon may already have been accounted for.” Clearly a significant opportunity exists to reduce carbon footprint before a structure is ever in use; selecting carbon efficient materials is a key part of the solution.
At GA we believe that calculating the carbon efficiency of materials should mean viewing embodied carbon from a whole life perspective. Going forward, sustainable buildings should be designed to reduce carbon use up front, but they should also offer resilient design that saves energy over the whole life term of a project too. We hope to see an increase in structures that keep materials in use, which can be disassembled and reused. In addition, we hope to see buildings which significantly reduce the need for maintenance too.
Construction professionals know that maintenance costs. A structure like the much loved, iconic Eiffel Tower for example is repainted every 5-10 years, creating a significant maintenance burden economically and extending its carbon footprint. The cost of man-hours lost when bridges need to be closed for repair, or the economic hit taken when scheduled rail services are delayed due to maintenance, are common examples of how a maintenance burden can impact the public purse but they also cost environmentally too. The impact becomes even greater when scaled up across the wider built environment.
- Increased carbon burden for new materials
- Increased carbon for transportation
- Increased energy spent on installation
- Greater impact of waste going to landfill
Overall, it is clear that selecting materials which offer lifetime reliability and reduced maintenance, plays a significant role in reducing whole life carbon footprint.
A recent publication by GA and our European counterparts EGGA puts maintenance reduction as a top priority for sustainable construction. Galvanized Steel And Sustainable Construction: Solutions for a Circular Economy showcases examples from across the UK and Europe that highlight the importance of choosing durable, zero maintenance materials to reduce carbon footprint over the long term.
A steel component which is completely covered with a durable, galvanized coating can last on average up to 60 years in the UK and Irish climate, sometimes over 100 years, making galvanized steel an ideal circular material. This kind of long-term durability is achieved at relatively low environmental burden in terms of energy and other globally relevant impacts. A galvanized coating also compares favourably to painting systems and research shows that across a variety of environmental impact categories, hot dip galvanizing is distinguished by lower consumption of resources and less pollution throughout its service life. A full comparison of the performance of hot dip galvanizing and paint systems can be found here.
Comparison for steel-framed car park over 60 year life: LCA results normalised to the highest contributory factor
Whether it is by reducing maintenance operations or avoiding the premature replacement of steel products, hot dip galvanizing will reduce the embodied carbon of construction. It can help reach sustainability targets by reducing waste and optimising efficient materials use.
Overall, hot dip galvanizing increases the lifespan of one of our most valuable construction materials, in terms of whole life carbon footprint the benefits are clear.