What is a green roof?
Updated: Aug 26, 2022
One of the hottest trends to hit today’s housing market is the green roof, also referred to as a living roof. But what is a green roof? A green roof is usually plants and vegetative resources on top of a man made structure. Most green roofs have a waterproofing layer, layer of soil, root barrier, and drainage and irrigation systems. Green roofs have been around since the age of the Vikings who would add bark and grass to the top of their homes to keep the draft out. In the 1960’s Germany began using them on their roofs to keep wild fires at bay. Now, many parts of Europe have adapted roofing to accommodate a living roof for both the public and private benefits. Recently the U.S. has caught on to the trend and major cities such as Nashville, Denver, Portland, Chicago and New York all require them as an option on new construction. Even the McDonald's headquarters in Chicago sports a fuzzy green hat! So what are the benefits and who can have a green roof? We answer these questions and more below….
Pros of having a green roof
Green roofs have many public and private benefits.
Public benefits include;
Aesthetics - green roofs provide a beautiful look that adds to the environment.
Environmental impact - green roofs use recycled materials. It also helps to eliminate waste that ends up in the landfills by prolonging the life of HVAC systems, heating systems and ventilation.
Stormwater management - In summer green roofing can hold 70-90% of precipitation and in winter can hold 25-40%. This helps relieve stress put on our sewer systems.
Air quality - Evaporation and dew allow the plant to cool the air in the summer which helps lower the use of AC systems. It also absorbs heat and can help warm air in the cooler temperatures. Lastly, plants absorb smog, dust and other pollutants in the air keeping air pollution down.
New job opportunities - with the growth of the market for green roofing, from design, construction, manufacturing and maintenance, we could see 190,000 jobs available in the near future.
Mental health - according to a blog from psychology today, living near or around green spaces can reduce stress, help with behavioral issues and encourage physical activity. Read the full article for all the benefits of green space living.
Provides food and a recreational area - In urban areas where green spaces are limited a green roof can provide an area that provides food, as well as agricultural opportunities.
Private benefits include;
Energy efficiency - with green space on the roof, it will help insulate the building, lowering the cost of both heating and cooling. This can save 20-25% energy costs to your business
Increased roofing durability - most roofs need to be replaced every 10 years. However, green roofs can last up to 45 years. Since they protect the water drainage layer of the roof as well as protect it against UV rays, debris as well as contraction and expansion.
Wildfires - Green roofs help keep fire retardation down and wild fires from spreading.
Noise reduction - having a green roof insulates the roof and therefore sound proofing the area.
Solar panel - they can help prolong the life of your solar panels by cooling the panels and the panels in turn shade the plants leading to less maintenance needed.
Cons of having a green roof
As with every change, there are also a few cons to having a green space.
Cost - having a green space can be costly. The average cost is $10-24 per square foot.
Structural change - You will need to ensure the structural load capacity, slope and existing roofing materials prior to installing a green roof.
Maintenance - once you install a green space you will need to have regular maintenance. Most companies that install green roofs have a maintenance add on.
More information on green roofs
Anyone in the US outside of Antarctica is able to have a green roof. Always check with your city for guidelines and possible tax breaks. Due to the structural capacities you need in order to have a green roof, this is something you should consult a professional on. For more information about green roofs check out green roofs.org.