The global shift toward sustainable practices has placed increasing emphasis on resource efficiency, waste reduction, and long-term environmental responsibility across all sectors, including construction and infrastructure.

Waterproofing membranes, a critical component of building envelopes, play a key role in ensuring durability and protection from water ingress. The lifecycle management of these membranes, particularly in refurbishment projects, presents an opportunity to align with sustainability goals.

Traditionally, the replacement of aged or damaged flat roof waterproofing membranes involves complete removal, often generating significant waste and requiring the use of new materials. This practice not only depletes natural resources but also increases the carbon footprint of such projects. By adopting overlay solutions, where a new waterproofing system is applied over the existing membrane, stakeholders can reduce waste and minimise the environmental impact of construction activities.

Raising the sustainability profile of flat roof refurbishment

With sustainability at the forefront of modern construction practices, the default approach should be to consider overlay options first. With the right expertise this can be achieved with modern, reinforced PMMA liquid applied waterproofing systems. An overlay with PMMA cold liquid roofing systems can raise the sustainability profile of flat roof refurbishments by:

Eliminating energy intensive hot works: Cold liquid applied systems are quickly and easily applied onto prepared substrates. Negating hot works, they not only satisfy insurers but also reduce any (often high) energy expenditure associated with traditional materials. Buildings can remain occupied, minimising disruption to their function.

Outstanding substrate adhesion: PMMA resins readily adhere effectively to a wide range of substrates including single plys, asphalt, felt, timber and glass. As specialist manufacturers, our know-how means that almost every type of waterproofing membrane in the UK can be overlaid with these modern materials with correct pretreatment and preparation.  

Reduce waste to landfill: Retaining the existing build-up in situ reduces waste generation as materials are reused rather than disposed of. In cases where some damage has occurred, partial build-up removal for localised repairs is possible, avoiding the need for complete roof strip-ups. 

Incorporating thermal improvements: Consideration of The Building Regulations Approved Document L (Conservation of Fuel and Power) is essential for refurbishment projects, especially in public buildings that aim to achieve energy savings. Overlay solutions can include thermal enhancements, such as tapered insulation schemes, which improve both thermal performance and drainage.

Achieve shorter project times year-round: Avoiding the need for a full roof strip up naturally reduces the time on site. With Triflex PMMA resins that are rainproof in 30 minutes and fully cure in 60 minutes, even in winter temperatures, large roof areas can be quickly watertight. Overall, that means less disruption and less days on site. In an increasingly unpredictable climate, weather windows are maximised, helping to keep projects on schedule. In turn that could mean fewer carbon intensive journeys for visiting workers as well as reduction in power for any associated activities. 

Durability and longevity: The long-term performance of the building envelope is an important consideration in the whole life carbon benefit of the building. BBA certification for waterproofing systems delivers confidence, with Triflex liquid roofing systems certified for 25 years expected life. 

But it’s not only a reuse of materials today to consider. With Triflex PMMA waterproofing systems that readily adhere to themselves, a future overlay with a Triflex PMMA liquid roof system can provide a long-term durability and warranty reset. All of which help to reduce the overall environmental impact of the project with life cycle benefits.

Key considerations for assessing overlay suitability

To evaluate the suitability of an existing waterproofing system for an overlay solution, several factors must be considered. This includes the type and current condition of the in situ waterproofing system, and the ability of the proposed system to adhere to the in-situ membrane. Triflex offer a suite of free services to the commercial and public sectors to assess the suitability for overlay, and provide bespoke project specifications.  

Thorough assessments include core testing to establish the type and state of the existing roof build up, as well as strength and adhesion testing of the proposed system on site. Additionally, condensation analysis and wind uplift calculations are also considered as part of our bespoke project specification to ensure a robust solution. Delivery of high-quality projects with meaningful warranties can be ensured through our trained and supported local authorised contractors.

For more information about our overlay solutions contact us today.