A growing demand in the construction industry, including residential projects, concerns the conversion of flat roofs into suitable surfaces for the installation of photovoltaic systems while complying with current regulations. Addressing this requirement, a recent project in the city of Bergamo - published on the INGENIO portal - has demonstrated how innovative technologies and high-performance materials can be combined to deliver safer, more durable, and more functional roofing systems.
The flat roof, characterized by a horizontal or slightly sloped surface, is designed to ensure proper water drainage.
In both residential and commercial contexts, the flat roof offers not only additional usable space but also the opportunity to integrate sustainable solutions such as photovoltaic systems and green roofs, contributing to energy efficiency and the redevelopment of urban spaces.
To fully exploit this potential, the roof structure must be carefully designed to ensure efficient rainwater drainage through minimum slopes, effective waterproofing layers, and adequate collection systems, in compliance with local climatic and weather conditions. This ensures the stability and long service life of the roof, making it an ideal platform for the installation of photovoltaic systems.
The intervention in question focused on the refurbishment of the roof of a residential building, with particular attention to waterproofing.
The need arose from the deterioration and removal of the previously applied synthetic membrane, which was replaced with double-layer polymer-bitumen membranes COPERPOL, 4.0 mm thick, with TEX surface finish, torch-applied.
A crucial aspect of the refurbishment was achieving the Bʀᴏᴏғ(t2) fire resistance classification, required for the subsequent installation of photovoltaic panels.
The TEX upper finish of the membrane was then coated with the white reflective product COPER SOLAR FIBER FR. This coating not only enhances external fire resistance, ensuring compliance with fire safety standards, but also increases the reflectivity of the roof, contributing to the overall energy savings of the building. This design choice provided an effective and long-lasting solution, fully compliant with external fire exposure regulations.
Key Products of the Solution
Among the materials employed, the COPERPOL membrane - with its APAO-based compound - stood out for its excellent flexibility at low temperatures, strong adhesion, and outstanding resistance to UV-induced ageing. Installed in a double-layer system, its high polymer content makes it a premium solution, ideal for professional applications where long-term durability and reliability are essential.
The TEX finish allows for the immediate application of liquid coatings, without the need for a minimum six-month waiting period for hydrocarbon migration to surface.
COPER SOLAR FIBER FR, applied as the finishing layer, is a fibre-reinforced elastomeric liquid waterproofing membrane, water-based, self-extinguishing, and reflective.
It has been specifically developed for COOL ROOF systems, reflecting solar radiation and mitigating the urban heat island effect.
The product creates a highly reflective barrier against UV rays, with an SRI (Solar Reflectance Index) of 97%. This significantly reduces the roof’s surface temperature, offering benefits in terms of indoor comfort and energy savings, while protecting and extending the service life of the waterproofing system.
A cooler roof surface allows photovoltaic panels to operate under optimal conditions, increasing their efficiency while simultaneously prolonging the lifespan of both the installation and the underlying membrane.
This intervention not only improved the safety and durability of the roof but also paved the way for the integration of green technologies, supporting the transition towards more sustainable and energy-independent buildings. A tangible example of how innovation in the construction sector can effectively address both energy demand and structural safety challenges.
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