Proteus Waterproofing Ltd

Many construction experts agree, that while green and blue roofs are visually appealing and eco-friendly, they present several distinct and often difficult waterproofing challenges. This is in addition for the need to cope with foot traffic, standing water and vegetation weight, all of which necessitates a waterproof membrane that can endure these factors and provide a robust barrier against moisture infiltration, but that is just the beginning, writes Justin Pitman, sales director at Proteus Waterproofing.

There are many different kinds of membrane types that can effectively waterproof green or blue roofs. Traditionalists may argue, however, that hot mastic asphalt, a trusted solution for decades, should remain the top choice due to its flexibility, durability and resistance to weathering. It remains a proven and popular option with building owners and specifiers.

Nevertheless, the traditional process of applying hot mastic asphalt, involving heating and melting the material, brings its own challenges and this is encouraging the shift to cold-applied solutions that offer the same seamless benefits without the risks. Hot work can endanger workers’ safety and create fire hazards, while heating asphalt contributes to air pollution and increases energy consumption, often disrupting operations in existing buildings.

Against this backdrop, membranes such as Proteus Cold Melt® are increasingly being chosen for green and blue roof applications. Cold Melt® combines the durability and flexibility of hot mastic asphalt with the ease of cold application and as its name implies, it is applied without heat, eliminating the need for hot work and any related safety hazards.

There are many similarities with mastic asphalt. Seamless application, for example, ensures that plant roots have no pathways, a potential issue with some membranes and like mastic asphalt, Cold Melt® is BBA-certified to last the lifetime of the substrate it is installed upon.

It is a membrane that provides excellent resistance to weathering, foot traffic, ponding water and much more. Its flexibility allows it to adjust to vegetation movement and withstand the weight of plants and soil, offering a more sustainable alternative to hot mastic asphalt as it incorporates recycled materials and reduces energy use during application.

Cold Melt® is more than just a waterproof membrane— it is a complete system that can be integrated into various roofing applications, including green roofs, inverted roof insulation systems and podiums. Its unparalleled durability provides complete waterproof protection throughout the roof’s life cycle.

The UK has seen a rise in green and blue roof installations, driven by environmental concerns, government incentives and a growing awareness of the benefits they offer. Estimates suggest that London leads the UK in green roof installations, accounting for around 42% of all green roofs. While data on blue roof installations is more limited, their adoption is trending upward, particularly in flood-prone areas.

Blue roofs are often integrated with Sustainable Drainage Systems (SuDS) for effective flood management, which is why government regulations and initiatives are increasingly promoting blue roof installations to address water management issues.

Crucially, there is a growing awareness of the advantages of green and blue roofs, with demand rising from both public and private sectors. Innovations such as lightweight substrates and self-watering systems are making these roofs more affordable and accessible.

Although specific data on the number of green and blue roofs installed in the UK is limited, available information shows a clear increase. The growing appeal of these roofing systems reflects a broader commitment to sustainable urban development and environmental protection.

Another reason perhaps, why architects and building owners are increasingly turning to solutions like Cold Melt®, which has become a game-changer in waterproofing, providing the high performance of hot mastic asphalt with the added benefits of cold application, sustainability and reduced odour.

As the demand for green and blue roofs continues to grow, driven by environmental concerns and evolving regulations, Cold Melt® is poised to play a pivotal role in the future of waterproofing. Its seamless integration into a variety of applications, coupled with its ability to meet the highest industry standards, makes it a preferred choice for those looking to deliver high-quality projects without compromising safety or sustainability.