Blue roofs

A blue roof is a roof that is designed to store and slowly release rainwater. Blue roofs typically consist of a waterproof membrane, a drainage layer and can include a growing medium. The growing medium can be planted with vegetation or left bare.

When it rains, the blue roof stores rainwater in the drainage layer. The rainwater is then slowly released over time, helping to reduce stormwater runoff and flooding. Blue roofs can also help to improve air quality and reduce energy consumption.

There are many benefits to having a blue roof, including:

• Blue roofs assist in rainwater storage, contributing to decreased stormwater runoff and potential flood mitigation. This can help to protect property and infrastructure from damage

• Blue roofs help to filter pollutants from the air, improving air quality

• They can help to insulate buildings, reducing the need for heating and cooling. This can lead to significant energy savings

• Blue roofs help to protect roofs from the elements, potentially prolonging roof durability. This can save money on roof repairs and replacements

• Blue roofs can provide habitat for birds, insects, and other wildlife, increasing biodiversity

The cost of a blue roof will vary depending on the size of the roof, the materials used, and the complexity of the installation. Blue roofs may have a higher initial cost compared to traditional roofs, however, their range of benefits can provide long-term value.

Yes, a blue roof can be installed on most existing buildings. However, it is important to have your roof inspected by a qualified professional to ensure that it can support the weight of a blue roof.

Blue roofs generally require low maintenance, typically only needing to be inspected once or twice a year. Any growing medium may need to be watered and fertilised periodically, but this will vary depending on the type of vegetation planted.

Yes, blue roofs contribute positively to the environment. They help to reduce stormwater runoff, improve air quality and reduce energy consumption. Blue roofs can also provide habitat for wildlife and increase biodiversity.

It can take up to two years for a blue roof with vegetation to mature. However, you will start to see benefits such as reduced stormwater runoff and improved air quality immediately.

A blue roof is designed to store and slowly release rainwater, while a green roof is designed to support plant growth. Blue roofs can be planted with vegetation, but they are not required to be. Green roofs, on the other hand, must be planted with vegetation. 

There are two main types of blue roof systems: retentive and detention.

• Retentive blue roof systems store rainwater in a growing medium, while detention blue roof systems store rainwater in a reservoir

• Retentive blue roof systems may have a higher initial cost compared to detention systems, yet they can provide additional benefits, such as improved air quality and reduced energy consumption

The best plants for a blue roof are drought-tolerant plants that can survive in a shallow layer of growing medium. Some good options include sedums, succulents and grasses.

Blue roofs generally require low maintenance. You will need to inspect the roof once or twice a year for any damage, leaks or blocked outlets. The growing medium may need to be watered and fertilised periodically, but this will vary depending on the type of vegetation planted.