Roofing solutions to reduce inner temperatures
High reflective membranes reflect UV rays and heat, thus reducing the surface temperature of the roof, as well as the inner temperatures. This leads to a lower energy consumption for air-conditioning systems, reducing the CO2 emissions. In many cases an air-co system can be totally avoided.
Looking for a reflective roof but white roof is not allowed?
Cool colour roof RENOLIT ALKORPLAN Smart is available in light grey or ivory colours. Thanks to its unique cool pigments, it is a valuable alternative to a white cool roof.
Application methods for single ply reflective roofing membrane
Cool roof RENOLIT ALKORPLAN Bright can be installed by mechanical fixation or glued to the support (adhered system).
The choice of installation system depends on the support or whether it is a new building or renovation project.
So, whatever your roof construction, purpose of the building or required installation method, RENOLIT ALKORPLAN Roofing products always have a suitable solution!
Mechanically fastened system
| Perfectly suited for lightweight metal deck structures. |
| Mechanical resistance (woven polyester reinforcement). |
| UV and fire resistance. |
Adhered system
| For concrete support. |
| For when the vapour control layer cannot be perforated. |
| Compatible with old bituminous membrane. |
Benefits of choosing our cool roof membranes for a reflective roof
Less energy demand
Better comfort
Less CO₂ emissions
Reduction “Heat Island” effect
Most used RENOLIT ALKORPLAN accessories for this product
RENOLIT ALKORPLAN Slip Resistant Walkway
Extremely slip resistant for PVC flat roof systems
See product
RENOLIT ALKORPLAN Design
An extruded standing seam profile with a triangular shape to be hot welded on PVC-P
See product
RENOLIT ALKORPLUS Multifunctional mounting profile
See productRENOLIT ALKORPLAN Cool roof FAQs
Solar Reflectance refers to the ability of a material to reflect solar energy away from the surface. This characteristic is particularly important for roofing materials because it can significantly impact the temperature of buildings, especially in warm climates. High solar reflectance helps reduce the amount of heat that enters a building, thereby lowering energy demands for cooling.
Solar Reflectance Index (SRI) is a metric that incorporates both solar reflectance and thermal emittance of roofing materials. It is expressed as a single value that indicates how well a material can reflect solar heat and stay cool in the sun. The SRI provides a more comprehensive assessment than solar reflectance alone, allowing for comparisons across different materials.
Calculation: a higher SRI indicates better performance in reflecting solar energy. RENOLIT ALKORPLAN Bright has an SRI of 115, demonstrating effective reflection capabilities (about 91% of solar rays).
- Energy Efficiency: Reduces the reliance on air conditioning, thus lowering energy costs and minimizing carbon emissions.
- Thermal Comfort: Helps maintain comfortable indoor temperatures in buildings, even those without air conditioning.
- Urban Heat Island Mitigation: Contributes to improved air quality and a reduction in the heat island effect in urban areas.
By using roofing materials with high solar reflectance and SRI values, designers and builders can not only achieve sustainability goals but also create more comfortable and energy-efficient spaces.
The urban heat island effect is a phenomenon where cities experience higher temperatures than surrounding rural areas. This is due to human-made materials like buildings, roads, and pavements that absorb and retain heat more efficiently than natural surfaces like grass or trees.
These materials also release stored heat more slowly, especially at night, contributing to localized warming. The reduction of green spaces exacerbates this effect, as vegetation helps cool urban areas through evapotranspiration.
Of course. The colour of the roofing membrane significantly affects the surface temperature and, consequently, the internal temperature of a building. For example:
- A dark membrane can reach up to 90°C on a warm summer day.
- A white membrane like RENOLIT ALKORPLAN Bright can be up to 45°C cooler. This difference can lead to an internal temperature reduction of up to 5°C, which can reduce or eliminate the need for air conditioning, lowering energy consumption and CO₂ emissions.
White membranes enhance PV performance in two keyways:
- Temperature Regulation: PV panels operate best at around 25°C. Darker roofs can cause panels to overheat, reducing efficiency by 0.5% for every degree above 25°C. White membranes help maintain optimal temperatures.
- Increased Reflectance: White membranes like RENOLIT ALKORPLAN Bright have a high albedo (0.8), reflecting more sunlight onto the PV panels. This can boost PV output by 3–4% compared to darker membranes.
Yes. White membranes reflect UV radiation, which is a major cause of degradation in roofing materials. This:
- Extends the lifespan of the membrane itself.
- Protects insulation materials like PIR, which can lose thermal performance when exposed to heat.
- Enhances the overall durability of the roof system. RENOLIT ALKORPLAN Bright, despite being only 1.5 mm thick, has a BBA-certified life expectancy of over 40 years.
Public entities and voluntary certification organizations promote the use of cool roofs because they help reduce the urban heat island effect, improve building energy efficiency, and contribute to environmental sustainability.
