Installing green roofs has numerous benefits to private, public, social, and economic sectors, as well as to both local and international environments. Green roofs provide similar functions, but every installation is unique. As such, technical performance depends on the building, climate, region, and type of green roof. Here are some of the general benefits of green roofs.
They minimize stormwater runoff
During heavy rains, runoff may overwhelm stormwater infrastructure, leading to considerable damage to fish habitats and waterways.
- Green roof systems retain rainwater and, with the help of plants, return some of this moisture to the atmosphere via transpiration and evaporation.
- Any stormwater that manages to leave the roof is slowed and decreased in volume.
- The retention of runoff relieves the stress on sewers and stormwater infrastructure.
- Decentralized stormwater mitigation enables cost savings that reduce the need to renovate or expand related infrastructure.
They are energy efficient
Green roofs cut back heat flux through the roof, providing significant cost savings as less energy is used for heating or cooling. Trimming the exterior surface of the building envelope is more productive than internal insulation.
- During summer, the building is protected from direct solar heat by the green roof.
- During winter, heat loss is minimized by extra insulation on the green roof
- The resultant energy conservation leads to less greenhouse gas emissions
They improve air quality
Dust particles in the air are trapped by plant leaves, and ambient temperatures are cooled by evapotranspiration
- Less heat + reduced ground level ozone = less smog
- Decreased urban-heat-island profile
- Reduced need for health-care services lead to societal cost savings
They serve as habitat
Rooftops are regarded as undisturbed areas can provide refuge for animals that are struggling to survive. These include ground-nesting birds like Killdeer, which use green roofs to nest and raise their young.
- Vegetated rooftop habitats may work as stepping stones, creating corridors that link to other patches in the natural habitat
- Natural habitats can work as templates for green roofs meant for biodiversity
- Low-maintenance green roofs can provide refuge for species such as ground-nesting birds
Green roofs last longer
Green roofs protect the waterproofing membrane from UV rays and intense temperature fluctuations. As a result, the waterproofing lasts twice as long as with traditional roofing. This means that the lifespan of the membranes below green roofs is twice as long as that of traditional membranes.
- Less material waste from re-roofing
- Reduced frequent re-roofing, minimum costs over time
Life cycle expenses are competitive
A green roof costs more to install than a conventional roof, but it has a competitive life cycle cost.
They provide ‘extra’ space
Green roofs utilize unused space within our cities. The rooftops can be used for urban agriculture or serve as social/recreational spaces.
- Amenity space for meetings, daycare, and recreation
- Better aesthetic views of neighbors in adjacent buildings
- Enhanced worker creativity and productivity
- Potential to improve urban food security via food production and rooftop gardening
Since the green roof industry is new in the market, it provides several employment opportunities:
- Manufacture and supply of roofing membranes and drainage layers, root repellent layers, irrigation systems, curbs, landscaping cloth, and other specialty items.
- Manufacture and supply of substrate, lightweight amendments, and soils, plants
- Design and engineering contractors, professionals, and landscapers, as well as companies that supply maintenance contracts.
Some of the other benefits of green roofs include:
- Helping us prepare and adapt to climate change by addressing the “Urban Heat Island Effect” and improving energy efficiency
- Opportunities to recycle compost and aggregate
- Providing natural views to hospital patients, thus reducing attention and medication needs
- Potential for reduced wastewater/stormwater charges from utility or municipality
- New projects can be approved faster
- Potential for grants linked to green roofs and energy efficiency
- Potential for larger floor area ratio/density bonusing
- Potential to satisfy green space/minimum parkland set aside, needs