Retrofitting an existing masonry cavity-walled building with a living wall can reduce the amount of heat lost through its structure by more than 30 percent, according to researchers at the United Kingdom’s University of Plymouth. The research was focused on the Sustainability Hub – a pre-1970s building on the university's campus. Researchers compared how two sections of the building’s walls retained heat.
Despite being on the same west-facing elevation, one of the sections had been retrofitted with an exterior living-wall façade. It was comprised of a felt-fabric-sheet system with pockets for soil and planting.
After five weeks of measurements, researchers found the amount of heat lost through the wall retrofitted with the living façade was 31.4 percent lower than that of the original structure. They also discovered daytime temperatures within the newly-covered section remained more stable than the area with exposed masonry, meaning less energy was required to heat it.
With buildings directly accounting for 17 percent of the United Kingdom’s greenhouse-gas emissions – and space heating accounting for more than 60 percent of all energy used in buildings – the new findings could help the United Kingdom achieve its net-zero commitments.
About 57 percent of all buildings in England were built before 1964, said Matthew Fox, a researcher in sustainable architecture and the study’s lead author.
“While regulations have changed more recently to improve thermal performance of new construction, existing buildings require the most energy to heat and are a significant contributor to carbon emissions,” he said.
The researchers aim to optimize the performance and sustainability of external living walls through research on the thermal properties and carbon sequestration offered by different plant and soil types.
Thomas Murphy, one of the study’s authors and an industrial research fellow on the Low Carbon Devon project, said, “With an expanding urban population, ‘green infrastructure’ is a potential nature-based solution that provides an opportunity to tackle climate change, air pollution and biodiversity loss. Living walls can offer improved air quality, noise reduction and elevated health and well-being. Our research suggests living walls can also provide significant energy savings to help reduce the carbon footprint of existing buildings.”
Alan Williams is a media and communications officer at the University of Plymouth.