The weight of an extensive green roof will range from about 13 to 30 pounds per square foot. Extensive green roofs are also the least expensive green roof type.
How much soil is needed for a green roof?
Extensive Green roofs don’t need to be deep as the recommended plants such as sedum, wildflowers and herbs don’t root deeply. As a general rule of thumb, it’s best to have a soil depth of at least 100mm. For example, 60mm of substrate (soil) and 20mm of pre-vegetated mats.
Which type of roof has a deeper more organics rich soil and can support a wider range of plants and trees?
Intensive green roofs have more soil and a deeper growing medium—sometimes several feet—that can support a more diverse plant selection, including small trees. Thus, they have more substantial structural loads and need more frequent maintenance and watering. They are usually accessible.
What is a semi extensive green roof?
Semi-Intensive Green Roof – A semi-intensive green roof system is characterized by small herbaceous plants, ground covers, grasses and small shrubs, requiring moderate maintenance and occasional irrigation. A typical growing medium depth for a semi-intensive green roof is 6 to 12 inches.
What are the two types of green roofs?
There are two primary forms of green roofing: intensive and extensive. These are differentiated by the amount of vegetation utilized. While extensive green roofs can support up to 25 pounds of vegetation per square foot, intensive green roofs can hold 150 pounds per square foot.
What can I plant on a green roof?
Top Ten Green Roof Plants
- White stonecrop – Sedum album. When viewed en-mass, the flowers of Sedum album look like swathes of candyfloss. …
- Widow’s cross – Sedum pulchellum. …
- Meadow saxifrage – Saxifraga granulata. …
- Two row stonecrop – Sedum spurium. …
- Birdsfoot trefoil. …
- Houseleeks. …
- Sea thrift. …
What is the cost of a green roof?
A small green roof (30-50 m2) with reasonable access would cost between $150 and $400 per square metre to install.
What are the disadvantages of green roofs?
Disadvantages of green roofs
- A greater expense than traditional roofs. Unfortunately for green roofs, they do tend to be slightly more expensive than the traditional option. …
- An increase in weight load. …
- Require extra maintenance.
Why do green roofs use a special soil mixture?
It is specially-made mixtures of soil and inorganic materials like crushed clay and perlite. This keeps the material lightweight and provides good water drainage. … The increased soil depth and plant density of intensive green roofs prevents heat from moving down to ceiling height.
What are the 4 main benefits of a green roof?
A green roof has many benefits at economic, ecological and societal levels. A green roof provides a rainwater buffer, purifies the air, reduces the ambient temperature, regulates the indoor temperature, saves energy and encourages biodiversity in the city.
How deep is an extensive green roof?
Generally speaking, ‘extensive’ green roofs are less than 6 inches deep, and, depending on depth, may support a range of plants. Think sedums (low-growing succulents), herbs, meadow grasses and perennials.
What is the difference between extensive and intensive green roof?
This is the easiest way to remember the difference – an extensive green roof probably has a shallow layer of substrate that covers a large area, whereas an intensive green roof often has a deeper layer of substrate, confined to smaller areas.
What are the benefits of green roofs?
Green roofs provide shade, remove heat from the air, and reduce temperatures of the roof surface and surrounding air. Using green roofs in cities or other built environments with limited vegetation can moderate the heat island effect, particularly during the day.
How long does it take to install a green roof?
Soil is placed on the filter fabric, and then the plants are installed. This may be done through seeds, by planting seedlings and small plants, or by installing trays of ready-grown plant material. Installation takes place over roughly 5 to 7 days, but it will take several weeks for the plants to establish themselves.
Can you walk on green roof?
Yes, you can occasionally walk on a Sedum roof. For instance, when you fertilize the roof once a year, walking on the Sedum plants is not a problem. However, be careful if it freezes: it is not advisable to walk on the vegetation if the plants are frozen, you may damage them.
Do green roofs need maintenance?
Maintaining your green roof. An extensive green roof is almost maintenance free. But your roof garden will always need a little maintenance. This includes removing weeds carried by the wind and applying fertilizer several times a year.