• News

    In roofing, blue is the new green

    March 2022


In the UK, climate change appears to be manifesting in record high summer temperatures and unparalleled levels of flooding due to excessively high rainfall events. These events are becoming more and more prevalent and the bottom line is - all this increased rainfall has to go somewhere.

Working together, the Government, the Environment Agency, local Councils and other bodies have developed strategies to try to mitigate and protect against these previously known as ‘once in a hundred years’ flood events.

They have the funding to tackle the large projects - buildings are being constructed above flood levels rather than on flood plains, there is more spending on flood defences, strategically planted trees are helping to protect wetlands, coastal barriers are being built – but what can be done on a smaller scale?

In UK towns and cities, flooding caused by storm water runoff is a significant problem. Part of the problem is that we have created mini concrete jungles with front gardens being paved over for car parking spaces, and back gardens being turned into patios or low maintenance decks.

It’s estimated that 5 million front gardens in the UK are now completely paved over. This loss of green space in favour of hard surfaces means rainwater cannot soak into the ground - gardens act like sponges - and instead, it flows into the nearest drains and sewers, overloading them and thus setting off localised flash floods. It’s the sheer speed of the water flow that causes the problem, leaving no time to prepare or take evasive action. So how can we slowdown that speed to make it more manageable?

From the 6th April 2015 it became compulsory for sustainable urban drainage systems to be considered in local policies and decisions on planning applications relating to major developments, to ensure that systems for the management of runoff are put in place, unless demonstrated to be inappropriate.

These sustainable urban drainage systems (SuDs for short) ensure that water falling across a development site is not simply channelled into storm water drains and then discharged into the local river. Instead it is designed to be drained in such a way as to mimic the natural environment.

This is where blue roofs come in. Blue roofs have evolved from the existing green roof concept that we are all familiar with on new builds and refurbishments. They can help to contribute to the SuDs requirements of a development by collecting and retaining rainfall within the actual roof structures, from which it can then be discharged at a controlled rate. This method comes into its own on sites where land is at a premium such as urbanised areas. In these areas, the installation of alternative attenuation techniques such as ponds or subterranean tanks may not be feasible.

The aim of a blue roof is to deliberately retain some or all of the water above a waterproofing membrane, rather than allowing it to drain from the roof straight away. This slows its flow down and the rainwater will either temporarily, or over a longer period of time, be released through a designated channel, such as a drain outlet, at a managed and controlled rate directly into sewers, waterways and river systems thus helping to mitigate any flood damage.

Now, if you are holding water on a roof, you have to be very sure that the waterproofing membrane you employ is up to the job. Proteus Waterproofing has developed a blue roof build up system which incorporates Cold Melt®, a seamless, waterproofing membrane that’s BBA approved, at its core. Being seamless, it means that there is just nowhere through which any water can escape. This is imperative because egress of water from any part of the roof can spell disaster for the building structure below.
Combine Cold Melt® with Proteus’ Pro-Living® components and you have a roof with blue roof certification that will last the design life of the structure on which it is built. What’s not to like!

Proteus can offer advice and expertise to support your blue roof installation, no matter how large or small. Just give us a call.

Talk to an expert today!