A new study reports that an existing present building with masonry cavity walls can be retrofitted with a green or living wall to decrease the amount of heat lost from its structure by over 30%.
The study performed at the University of Plymouth focused on the Sustainability Hub—a pre-1970s building located on the university campus—and performed a comparison of how effectively two sections of its walls withheld heat.
Although one of those sections was located on the same west-facing elevation, it had been retrofitted with an exterior living wall façade, including a flexible felt fabric sheet system that had pockets enabling soil and planting.
Once the measurements were over after five weeks, scientists discovered that the amount of heat lost from the wall retrofitted with the living façade was 31.4% lower compared to that of the original structure.
Furthermore, they found daytime temperatures inside the newly-covered section stayed more stable compared to the area with exposed masonry. This implies less energy was needed to heat it.
The study is considered one of the first to determine the thermal influence of living wall systems on present buildings in temperate scenarios and was performed by academics linked with the Sustainable Earth Institute of the University.
In the Building and Environment journal, the researchers add that although the concept is comparatively new, it has earlier been demonstrated to offer a host of advantages, like added biodiversity.
But with buildings that directly account for 17% of UK Greenhouse Gas Emissions—and space heating accounting for more than 60% of all energy consumed in buildings—the results of the new study can be a turning point for the United Kingdom to achieve its net-zero commitments.
Within England, approximately 57% of all buildings were built before 1964. While regulations have changed more recently to improve the thermal performance of new constructions, it is our existing buildings that require the most energy to heat and are a significant contributor to carbon emissions.
Dr Matthew Fox, Study Lead Author and Researcher in Sustainable Architecture, University of Plymouth
“It is, therefore, essential that we begin to improve the thermal performance of these existing buildings if the UK is to reach its target of net zero carbon emission by 2050, and help to reduce the likelihood of fuel poverty from rising energy prices,” Fox added.
The University is famous throughout the world for its study into sustainable building technologies, and the results of this study are already being implemented as part of the University’s Sustainability Hub: Low Carbon Devon project.
Assisted by financial support from the European Regional Development Fund (ERDF), the three-year £2.6 million program has been examining low carbon solutions via study and aid for local enterprises.
Particularly, this concept of the project is finding ways to improve the sustainability and performance of external living walls in sustainable building design by analyzing the thermal properties, and carbon sequestration, provided by various plant and soil types.
With an expanding urban population, ‘green infrastructure’ is a potential nature-based solution which provides an opportunity to tackle climate change, air pollution and biodiversity loss, whilst facilitating low carbon economic growth. Living walls can offer improved air quality, noise reduction and elevated health and well-being.
Dr Thomas Murphy, Study Author and Industrial Research Fellow, Low Carbon Devon Project, University of Plymouth
“Our research suggests living walls can also provide significant energy savings to help reduce the carbon footprint of existing buildings. Further optimizing of these living wall systems, however, is now needed to help maximize the environmental benefits and reduce some of the sustainability costs,” Murphy added.
Fox, M., et al. (2021) Living wall systems for improved thermal performance of existing buildings. Building and Environment. doi.org/10.1016/j.buildenv.2021.108491.