Buildings with green roofs (also known as living roofs) are becoming more popular for the many advantages they supply.
While green roofs are more costly to install, over time, the benefits outweigh the costs. Lawrence Berkeley National Laboratory researchers found that green roofs provide a measurable financial and environmental impact over a 50-year lifespan. The financial benefit was $14 per square foot compared to a conventional roof.
Buildings with green roofs reap the lower cost of the extra insulation that a green roof supplies, as the building is better shielded against heat and cold.
Additionally, green roofs last much longer than conventional roofs, lowering costs, waste, and materials allocated to roof replacement.
Benefits to Humans
Green roofs increase visual appeal by integrating nature into building features that are normally characterized by stark concrete and steel. Increasing human connection with nature by building natural landscapes into work and living environments benefits mental and physical health and wellbeing, as well as increases productivity and quality of life. Studies have even shown that patients with views of nature have shorter hospital stays.
The extra insulation that a green roof provides to a building decreases temperature fluctuation indoors and increases comfort to those inside the building.
Benefits to Cities and the Environment
Natural surfaces like vegetation and soil absorb heat from the sun, whereas materials such as concrete and asphalt reflect the sun’s rays. This reflection creates a condition known as the “urban heat island effect” in a city’s downtown core, which leads to higher surface temperatures of buildings and an overall increased ambient air temperature in city centers over those in rural environments (by several degrees). Plants on green roofs also release moisture into the air (through a process called evapotranspiration) which dissipates surrounding ambient heat.
A conventional roof can be as much as 30-50°C warmer than a green roof. This is one of the reasons why many cities have a minimum requirement for dedicated green spaces and parkland, which green roofs count toward. The LEED certification system gives 7 credits toward buildings with green roofs for the environmental benefits these roofs provide.
Green roofs also reduce stormwater runoff and filter pollutants from rainfall. They allow for reusing of recycled materials (like aggregate and compost) and reduce greenhouse gas emissions. The environmental benefits of green roofs can lead to faster building approval times in some cities, grant opportunities, and density bonusing or floor area ratios.
Maintenance of Green Roofs
LECM went through the training and testing to become a Green Roof Professional accredited company, which is a designation awarded to companies who have achieved specific knowledge in management and maintenance of green roof environments. We’d love to help you manage your green roof or have a conversation with you about building a green roof as a part of your next building construction project.
Talk to us today.