World Green Roof Day – June 6, 2022

World Green Roof Day is celebrated on June 6 every year to appreciate the beautiful green roofs that contribute to a better environment and raise awareness about their importance to climate change. Did you know the first record of green roofing was the Hanging Gardens of Babylon, planted in Iraq in 500 B.C.? Also known as living roofs, they consist of vegetation that partially or completely covers a waterproofing system. Green roofing lowers the cost of cooling and reduces stormwater runoff. World Green Roof Day is an initiative by Chris Bridgman and Dusty Gedge, experts in sustainable green roofs.

History of World Green Roof Day

If we are to believe the ancient texts, we can confidently trace the first green roof to the Hanging Gardens of Babylon, one of the seven wonders of the ancient world — planted in Iraq in 500 B.C. According to ancient Greek, Roman, and Assyrian texts, these gardens were grown over stone pillars and roofs. They were made up of trees and fauna found in the Babylonian mountains, and they supplied shade for people and cooled buildings’ interiors. Vikings also used green roofs during the Middle Ages to survive the harsh climate of their region. These green roofs were constructed using sod and grass, with substrates and water-retaining membranes made from birch wood. The roofs provide protection from harsh weather, good insulation during the winter months, and a cool interior in the summer. These Norse houses were so durable that their remnants are still found today.

Modern green roofing began in the early 20th century in Germany. The movement is said to have kick-started when Gerda Gollwitzer and Werner Wirsing published their book entitled “Roof Areas Inhabited, Viable and Covered by Vegetation.” In 1969, the movement gained traction when the government commissioned the construction of a green roof at GENO Pharmaceuticals headquarters. Green roofing expanded across Germany between the 1970s and 1980s as public interest in sustainable architecture grew, covering 13 million square meters by the mid-1990s.

In the United States, green roofing first appeared in the Rockefeller Center in the mid-1930s. It has since become part of the country’s social elements, with states such as New York and San Francisco offering tax incentives to developers who integrate green roofs in their buildings. Green roofs are found in most countries in Europe, Canada, the U.S., Egypt, and Costa Rica.

World Green Roof Day timeline

605 B.C. — 562 B.C.
The Hanging Gardens of Babylon

Legend has it that King Nebuchadnezzar plants the Hanging Gardens of Babylon, making them the first green roofs.

The Middle Ages
The Vikings Build Roofs

The Vikings use sod and grass to construct roofs for insulation against harsh conditions.

1900s
Modern Green Roofing

Gerda Gollwitzer and Werner Wirsing publish a study “Roof Areas Inhabited, Viable and Covered by Vegetation,” kickstarting the green roofing movement in Germany.

Present
Green Roofs are Here to Stay

Green roofs are now part of urban architecture in the United States and countries in Europe.

World Green Roof Day FAQs

Where in the world is green roofing most popular?

Germany has the highest number of green roofs. About 10% of its roofs are greened.

Where is the biggest green roof?

The Millennium Park in Chicago, United States, is considered the largest green roof project in the world at 24.5 acres.

What is the purpose of a green roof?

Green roofs help to reduce stormwater runoff, the heat island effect, and energy consumption, among other environmental benefits.

World Green Roof Day Activities

  1. Take pictures of gorgeous green roofs

    The essence of World Green Roof Day is to showcase the beauty of green roofs. If you live in an area with green roofs, take exciting pictures of them and share them on social media. Don’t forget to use the hashtag #WGRD.

  2. Raise awareness about green roofs

    Green roofs have the potential to help limit the impact of climate change, and the world needs to know about that. You can play your part this World Green Roof Day by talking to family, friends, and connections about their importance and calling for public initiatives to allow the construction of more green roofs.

  3. Organize a green rooftop event

    Another way to celebrate World Green Roof Day is to throw a green roof party or hang out. If you don’t have a green roof, you can check if there’s someone near you who has one. Ask them if you could use their green roof to promote World Green Roof Day and encourage more people to build green roofs.

5 Fascinating Facts About Green Roofs

  1. They absorb rainwater

    Green roofs can absorb up to 80% of rainwater and prevent flooding.

  2. They reduce noise

    Green roofs act as sound barriers, reducing external noises by eight decibels compared to conventional roofs.

  3. They are long-lasting

    Green roofs can last twice as long as regular roofs.

  4. They are fire-resistant

    Plants usually contain a lot of moisture and provide a fire-resistant layer.

  5. They are an investment

    A green roof can extend the life of a regular roof by protecting it from the elements, such as sun and rain.

Why We Love World Green Roof Day

  1. Green roofs are essential to climate change

    The planet is fast warming and might become unlivable for humans in a few years if something drastic is not done. Green roofs are one of the solutions that can help tackle the issue. With every home having a green roof, we can reduce carbon emissions, especially in urban centers.

  2. Green roofs offer health benefits

    Aside from serving as a sound barrier, green roofs can help filter pollutants and carbon dioxide from the air, providing cleaner, fresher air. That cuts down the rate of cardiovascular diseases such as asthma. Green roofs also filter heavy metals and pollutants from rainwater.

  3. Green roofs help prevent urban flooding

    Studies have shown that green roofs can help reduce water runoff by 75% and retain about 75% of rainwater during rainstorms. That makes green roofs a crucial component of water management systems in cities and areas that experience heavy flooding.

World Green Roof Day dates

YearDateDay
2022June 6Monday
2023June 6Tuesday
2024June 6Thursday
2025June 6Friday
2026June 6Saturday

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