What is a green roof made of?
Before we answer that question, let’s answer the question most people still have: “What is a green roof?” A green roof is when the roof of a structure has had a garden built and planted on it with a waterproof membrane under it. The green roof garden may have flowers and shrubbery, or it may be a vegetable garden where the habitats of the building can get fresh food. Under the waterproof membrane, there is a drainage and irrigation system installed so that the water doesn’t accumulate and weigh on the structure.
Green roofs are installed on rooftops that are flat or have a slightly sloped, and have three primary categories:
- Extensive: Contains a shallow medium of six inches or less, creating a limited roof load with limited plant variety. Minimal watering is required, and the green roof is usually not accessible.
- Intensive: Contains added level of soil with a deeper medium, even at several feet, with a more disparate selection in plants and small trees.
- Semi-intensive: This is a combination of the first two.
The elemental composition of a green roof contains of the following:
- Growing medium
- Filter membrane
- Drainage layer
- Waterproof and root repellant layer
- Roofing membrane support
- Thermal insulation
- Vapor control layer
- Structural support
Can you put a green roof on an existing building?
Yes, in many cases, installing a green roof on an existing structure is sometimes preferred by the installing contractor. Green vegetative roofs are popping up in big and small cities, providing beauty and more. It is recommended to use the services of a professional that knows how to install a green roof because of the details involved in doing it correctly.
The weight limitations of a roof will depend on which type of green roof is the best option, extensive or intensive, and if it can be retrofitted. There is the need to choose the right type of roof membrane, drainage, and insulation that are often learned by experience.
How do you maintain a green roof?
Like a typical garden, a green roof garden has some required maintenance, especially during the first season or two, as it takes root and develops. How much maintenance is determined by how which type of green roof garden you plant: Extensive or Intensive. In general, the seven things that will need human interactions are:
- Unwanted plants weeded out.
- Keep the drainage clean and clear.
- Biannually, add compost
- Unwanted plants weeded out again.
- Water only if needed.
- Treat for disease and pests as needed.
- Keep a detailed log of maintenance performed.
Why get a green roof?, Is green roof good?
A green roof adds beauty to an area often neglected. A green roof also provides many benefits to the building and the area around it, which we have summarized here:
- Economically Beneficial: The upfront cost is expensive to install a green roof, but the economic benefits that follow are many, starting with the increased R-value for the roofing system. With this extra layer of insulation, the internal temperature is lower, easing the workload of the HVAC system, using less electricity.
- Stormwater Management Improved: A green roof provides help in controlling stormwater runoff and retention.
- Urban Heat Island Effect Reduced and Air Quality Improved: A garden roof can help lower the temperature around the building, helping to reduce the urban heat island temperature.
- Greenhouse Gas Emissions Reduced: With reduced cooling loads, the greenhouse gas emissions from HVAC equipment is reduced.
- Roof Life Extended: A green roof can extend the existing roof’s life expectancy by protecting it from UV rays and extreme temperatures.
Do green roofs leak?
A green roof will not create any leaks when installed by a professional. A green roof will extend the life of the existing membrane because of the thick protective layer it provides against mechanical damage, extreme fluctuation in temperature, and intense UV rays.
Sold on A Green Roof Yet?
So, we know a green roof is more costly to install, and it will require maintenance. Just how long does a green roof last for that extra cost and manpower? In Europe, where a green roof is more commonplace than here in America, they have been known to last 30 years up to 50 years. What are the pros and cons of having a green roof?
- Environmentally good
- Lowers energy costs
- Little maintenance
- Longer lifespan
- The initial installation cost of a green roof is higher than a traditional roof
- A green roof is heavier and may require additional structural support
Overall, it is worth considering having a green roof installed. A structural engineering report is recommended by roofing experts no matter how new the building. Then making sure you commit others to help with the maintenance and upkeep so that the burden doesn’t fall on one person. Once they see the beauty and fruits of their labor, more people may join in with the green roof upkeep. Call 817-349-0016 today for your green roof installation in Fort Worth, TX.