"Replacing Asphalt with Polymers": The Core Role of Polymer Materials in Photovoltaic Roofs and Green Roofs

Under the guidance of the "Dual Carbon" goals, the construction industry is undergoing a profound green transformation. As a critical component of building energy efficiency, roofing systems directly impact the whole-life carbon emissions of buildings. Traditional asphalt-based waterproofing materials, plagued by high production energy consumption, construction pollution, and short service lives, struggle to meet the demands of modern green buildings. Polymer waterproofing materials, represented by TPO and HDPE, are playing an irreplaceable core role in two major application scenarios—photovoltaic roofs and green roofs—by virtue of their exceptional weatherability, environmental friendliness, and functional integration capabilities.

Part 1: Photovoltaic Roofs: Why TPO is the "Perfect Partner"?

Photovoltaic roofs integrate solar modules with building roofing systems, typically requiring a design life of over 25 years. However, traditional profiled steel sheet roofs commonly begin leaking within 3-5 years and require panel replacement every 8-10 years, creating a severe mismatch with the lifespan of PV modules. This leads to the ironic situation where "roof repairs waste steel, and PV carbon reduction efforts are in vain" . The emergence of TPO (Thermoplastic Polyolefin) waterproofing membranes fundamentally resolves this contradiction.

1. Extended Weatherability, Matching PV Module Lifespan

The core advantage of TPO membranes lies in their plasticizer-free homogeneous structure, granting them durability that matches PV modules. Accelerated weathering tests show that high-quality TPO membranes subjected to 10,000 hours of irradiation (far exceeding the national standard of 2,500 hours) exhibit a performance degradation rate of less than 5%, with an exposed service life exceeding 25 years . This allows the roofing waterproofing system to be designed, constructed, and warranted synchronously with the PV modules, completely eliminating later-stage repairs that would disrupt photovoltaic power generation.

2. UV Resistance and Temperature Tolerance: Safeguarding PV System Stability

PV module operating temperatures can reach over 80°C, accompanied by year-round UV exposure . The polyolefin molecular structure of TPO membranes offers inherent UV stability. Combined with efficient antioxidant systems, they maintain flexibility and strength across extreme temperature differentials from -40°C to 120°C, with low-temperature bendability showing no cracks at -40°C . Butyl-based polymer membranes demonstrate ozone resistance over 10 times that of natural rubber and airtightness 20 times greater, enabling long-term endurance in extreme environments .

3. Energy Efficiency: The "Cool Roof" Effect of White TPO

White TPO membranes achieve a solar reflectance of ≥85%, reducing indoor temperatures by 3-5°C while lowering PV module surface temperatures to enhance power generation efficiency by 1.2%-1.8% . This "cool roof" characteristic not only reduces building cooling energy consumption but also optimizes the operating environment for PV modules, delivering dual energy-saving benefits.

4. Protecting PV Mounting Systems: Achieving Integrated Sealing

Penetration points such as PV mounting brackets and cable entries are high-risk areas for leakage. TPO membranes utilize hot-air welding technology, achieving seam peel strength ≥4.0 N/mm or membrane failure, forming an integrated sealed layer with strength matching the parent material . Combined with specialized PV mounting base waterproofing designs, this enables reliable integration between brackets and the waterproofing layer, eliminating leakage risks.

Part 2: Green Roofs: The Root-Penetration Resistance Mission of HDPE and TPO

Green roofs (rooftop gardens, underground parking deck roofs) beautify cities and regulate microclimates while imposing dual requirements on waterproofing materials: physical root resistance and chemical stability. Plant roots possess strong penetrating power, and root exudates can accelerate material aging. HDPE and TPO root-resistant membranes have therefore become the mainstream choice for green roofs.

1. The Science of Root Penetration Resistance

According to GB/T 35468-2017 "Root-resistant waterproofing membranes for green roofs" , root-resistant materials must pass at least two years of plant box testing without root penetration . The root resistance mechanisms of TPO and HDPE membranes include:

Physical Root Resistance: High material density and mechanical strength, with tear resistance exceeding 60 N/mm, preventing mechanical root penetration .

Chemical Stability: Free from heavy metals harmful to plants, with mold corrosion resistance reaching Grade 0 or 1, rendering root exudates unable to molecular structures .

2. HDPE's Puncture Resistance Advantage

HDPE (High-Density Polyethylene) membranes are renowned for their exceptional mechanical strength, with tear resistance reaching over 600 N/mm. They are particularly suitable for high-strength applications such as underground planting decks. Their pre-applied bonding technology achieves permanent full-surface adhesion with cast-in-place concrete, eliminating water migration and providing dual protection for green roofs.

3. Ecological Benefits and Sponge Cities

The combination of green roofs and polymer membranes perfectly aligns with the Sponge City development concept. Integrated waterproofing and drainage systems enable rainwater "infiltration, retention, storage, purification, utilization, and discharge," while reducing urban heat island effects and increasing ecological space .

Part 3: Canlon: An Innovation Leader in the Polymer Sector

As a leading enterprise in China's polymer waterproofing membrane industry, Canlon has established a comprehensive product portfolio and system solutions for photovoltaic roofs and green roofs.

1. TMP Integrated Panel: Revolutionary Innovation for Photovoltaic Roofs

Addressing the corrosion and leakage vulnerabilities of traditional steel roofs, Canlon innovatively developed the TMP Integrated Panel System. This system bonds exposed TPO membranes with galvanized steel sheets through a specialized process, achieving integrated corrosion and waterproofing protection. It effectively extends steel roof service life to over 25 years, matching the full lifecycle of PV power stations . The product has been granted a national invention patent, becoming the industry's first innovation integrating polymer waterproofing materials with steel roofing.

2. Root-Resistant Product Matrix

TPO Root-Resistant Membranes: Produced on imported production lines, achieving domestic of glass-fiber reinforced (Type G) and glass-fiber reinforced with fleece backing (Type GL) products, with accelerated aging tests reaching 10,000 hours 

PVC Root-Resistant Membranes: Certified to German FLL standards, suitable for green roofs

Green Roof Deck Drainage Systems: Integrated with waterproofing systems to meet Sponge City requirements 

3. International Certifications and Project Track Record

Canlon's polymer industrial park features complete imported production lines from Italy and Germany, with an annual planned capacity of 100 million square meters . Products have obtained EU CE certification and are widely applied in landmark projects both domestically (Fujian Fuqing Nuclear Power Plant, Beijing Daxing International Airport Project - Luban Award winner) and internationally (US Yacht Terminal Project), earning global customer trust through "leak-free" performance.

Conclusion: Replacing Asphalt with Polymers—The Inevitable Choice for Green Buildings

"Replacing asphalt with polymers" represents not merely a material substitution but an of architectural philosophy. In photovoltaic roofing, TPO has become the ideal partner for green energy buildings through its lifespan-matching durability, energy-saving reflective properties, and sealing capabilities that protect mounting systems. In green roofing, HDPE and TPO provide reliable foundations for urban vertical greening through dual guarantees of physical root resistance and chemical stability.

As a leading enterprise in the polymer waterproofing field, Canlon is driving the transformative leap of roofing systems from "functional components" to "energy-generating assets" through innovative products such as TMP Integrated Panel and MBP series. On the journey towards carbon neutrality, choosing polymers means choosing a green commitment that lasts as long as the building, coexists with nature, and marches into the future together.