All You Need To Know About A Blue Roof
The blue roof refers to a system of detention ponds where stormwater is temporarily collected and stored before released slowly once the rain has stopped. The blue roof can be compared to a temporary sponge mimicking the hydrology of a site before any construction of a building. Water collection can be provided from building rises that lead to water pooling in designated areas, as well as the installation of customized trays to collect and release water.
What Are The Advantages Of A Blue Roof?
When combined with a sewer system in urban areas, rain can easily overwhelm the system sending any untreated sewage into rivers, lakes and streams. This is typically referred to as a combination system overflow and involves single sewage systems to handle both the stormwater and sewage. It does not take much rain to trigger a combination system overflow. For instance, in New York City, this issue can be experienced after as little as one half-inch of water overflows. Blue roofs can help reduce the risk of this occurring.
A further advantage to the use of a blue roof is that it significantly lowers the building’s cooling costs if combined with light-colored roofing material. Moreover, some systems choose to spray the stored water back onto the roof using controlled mechanisms and increasing cooling. It is also possible to use the stored water for landscaping or in locations where green roofing is an option. Some companies choose to use the stored water for recreational purposes, such as providing water for fountains or to cool a roof walkway.
What Else Must I Consider When Using A Blue Roof?
Before installing a blue roof on the building, it is important to take certain considerations into account.
#1: The Cost
In the majority of cases, the blue roof is far less costly than a green roof with an average cost of less than $1 per square footage.
#2: The Load Capacity
Statistics show that a single inch of water weighs approximately 5.2 pounds per square foot, and this can add to the weight of a blue flat roof. Before installing a blue roof, it is recommended you have a professional engineer verify your construction can support the weight of the water stored.
#3: The Standing Water
In addition to the risk of leaks, any standing water can also attract bacteria and mosquitoes. This is detrimental as it increases the risk of Zika and West Nile viruses. If you plan on installing a blue roof, it is advised you first take steps to reduce mosquito breeding.
#4: The Roof Membrane
As with certain pipe supports and other roof equipment, any items puncturing the roof membrane can result in roof leaking. One of the best methods to avoid this issue is by using non-penetrating detention trays.
#5: The Warranty
Certain warranties indicate that alterations to a roof surface can make the warranty null and void. It is essential you check the fine print before installation of the blue roof.
#6: The Local Regulations
Always check with your local authority before even commencing work and in fact even before the planning as the rules and laws differ from council to council.