What is a blue roof?

A Blue Roof is a Flat Roof, designed explicitly to allow controlled attenuation of rain fall during heavy and storm events. The system collects rainwater and then slowly releases water once the rain has stopped, this slow release of water prevents the risk of sewers waterways and river systems being overwhelmed and reduces the risk of flooding. It acts as a temporary sponge, mimicking the hydrology of the site before the building was constructed. The water collection can be accomplished through everything from building risers that cause water to dam up in designated areas to installing custom-designed trays for collecting and releasing water. However, it is important to note that a blue roof is not to be considered as a water storage solution.

What are the benefits?

Blue roofs for can be incredibly advantageous, some of the benefits of choosing this type of roof include:

  • Reducing the cooling cost for your building- blue roofs can seriously help to keep your building cool, saving you money on air conditioning. The blue roof itself helps to keep your building cooler than usual, but this will be amplified if you choose a light colour material for the roof design. In some blue roof systems, some of the water collected can be then sprayed back over the roof, to amplify this cooling effect even further.
  • Reducing the Heating cost for the building – Being extremely cost-effective blue roof can help to control the temperature of the building and can act as another form of insulation, significantly reducing heating bills.
  • Reducing the risk of localized flooding- in recent years, flooding in towns and city centres has become an annual problem, with business owners and homeowners both at risk. This is because in rural areas, the ground can soak up most of the water but in urban areas, concrete does not provide the same benefit. Instead, the drains overflows, and flooding occurs. Blue roofs are specially designed to mitigate this urban flooding and reduce the risks, by controlling the flow of water to drains and river systems and preventing them from becoming overwhelmed. This can be a great advantage if your commercial property is in a place where flooding often occurs.
  • Blue Roofs require very Little maintenance and are self-sustaining.
  • The water collected on the roof can be recycled and used for water features etc.

What else do I need to know?

There are a few things to consider before installing a blue roof on your building:

  1. Cost – In most cases, blue roofs are significantly less expensive than green roofs.
  2. Load capacity – One inch of water weighs 5.2 pounds per square foot, which can add a significant load to a roof. Have an engineer verify that your building and roof can support the weight of the water being stored.
  3. Standing water – In addition to the potential for leaks, standing water also attracts mosquitoes and other insects.
  4. Your roof membrane – As with pipe supports and other rooftop equipment, anything that punctures the membrane introduces the possibility of leakage. Non-penetrating detention trays are the best way to avoid that problem.
  5. Your warranty – Some warranties stipulate that any alterations to the roof’s surface voids the warranty. Check your warranty before installing a blue roof (or beginning any other roofing project).

Would a blue roof be suitable for your property?

Blue roofs are suitable for a wide variety of building types, including industrial, domestic, and commercial properties. The stormwater attenuation is designed to fit within the footprint of the building, this means that the blue roof is ideal for urban and built-up environments, where ground space is limited. However, a structural engineer will need to work with you on a blue roof project because of the weight of water, blue roofs do have weight load implications. For more information about blue roofs, and what they can offer your property, get in touch with our blue roof Technical team today!