Reflective coatings, also referred to as “cool roof” paints, are a superlative method for eliminating the extreme heat in India. Their operation is based on the principle of reflection, which means that sunlight is bounced back instead of being absorbed by the roof, thus producing a huge drop in the roof’s temperature and making the indoors cooler. Consequently, the air conditioning, which is one of the major contributors to electricity consumption in summer, is not required, resulting in a reduction of both energy and money.
Nevertheless, among the many people who have used these coatings, it is common to hear that the coatings have given up on them earlier than expected in India. The reasons for Why Reflective Coatings Fail in India’s Climate are the peeling, cracking, and loss of efficiency of coatings. This should not only interpreted as a sign that the technology is faulty in its very nature, but also the extreme and diverse climate of India poses very specific, very aggressive challenges in the area of standard coatings that they are often not strong enough to endure.
Reasons Reflective Coatings Fail in India’s Climate
A concise and simple-to-grasp explanation of the major factors Why Reflective Coatings Fail in India’s Climate is provided below. The discussion spans from the extreme weather to the erroneous practices during the application process.
The Triple Threat: Extreme Heat, UV, and Thermal Stress
India’s atmosphere is a rigorous place for any substrate, but particularly so for coatings. It is an interplay between three factors that finally lead to the painting film’s destruction.
The Constant UV Bombardment
Heat is not the only thing that the sun delivers; it also radiates Ultraviolet (UV) radiation. Ultraviolet rays are the very active particles of light that can be compared to very small wrecking balls attacking the organic polymers (the plastic-like binders) that are used to hold the coating together.
- The Technical Failure: This process is termed photodegradation. UV light ruptures the bonds between the atoms and molecules in the coating material. This quickly renders the surface to be of a chalky nature (the phenomenon is known as chalking) as the binder gets degraded and the pigment particles are left loose.
- The Outcome: The coating gradually loses its brilliance and freshness, becoming dull or yellow. A dull coating has the property of absorbing heat more than reflecting it, which is contrary to the aim of a “cool roof.”
Aggressive Thermal Cycling
Picture the roof surface on a hot summer day in Delhi or Rajasthan. The temperature can reach 65 degrees Celsius or even higher, and then drop drastically at night. This drastic change is referred to as thermal cycling.
- The Technical Failure: During the hot roof period, the coating swells. When the temperature drops, the coating shrinks. The different rates of expansion and contraction of the coating and the roof (mostly concrete) create an immense stress at the bond line through constant push and pull.
- The Result: This stress directly results in surface cracks (hairline fractures) and subsequently in the loss of coating adhesion (delamination) as the coating keeps on losing its hold on the substrate, which in this case is the roof.
Poor Surface Preparation
A coating is only as strong as its foundation. In the construction industry, poor or inadequate surface preparation is arguably the number one reason for coating failure, and it is a common issue on Indian construction sites.
Contamination and Lack of Adhesion
A roof surface should be absolutely clean before a coating is applied. The cleaning process involves the removal of old paint, dust, oil, grease, and, primarily, soluble salts.
- The Technical Failure: Chemical bonding between the coating and the roof is impossible if the surface is contaminated with dust or oil. It is similar to sticking a sticker on a dusty wall; it will come off easily. Additionally, if soluble salts are present (particularly in coastal regions), they will hold moisture, and that will cause blistering as mentioned previously.
- The Result: Improper adhesion of the coating that results in immediate peeling (delamination) starting at the edges and progressing rapidly.
The Cure Time Mistake
Coatings require a specific amount of time to fully dry and achieve their final strength—this is called curing. Many applicators, rushing to complete a project, apply the second coat or expose the roof to rain before the first coat has fully cured.
- The Technical Failure: Rushing traps solvents inside the coating film or prevents the binder molecules from forming a strong, cross-linked network. The coating remains soft and weak.
- The Result: A soft coating is easily damaged by foot traffic, hail, or subsequent coats, leading to premature wear and tear, and a coating with poor overall durability.
Substandard Materials and Application Errors
The final breakdown often comes down to the quality of the product and how it’s put on the roof.
Low-Quality Coating Formulation
The term “reflective paints” includes low-quality ones as well. The superior quality cool roof coatings are specially made with a mixture of ceramic microspheres and high-grade acrylic polymers to survive UV rays as well as be flexible.
- The Technical Failure: Inexpensive or non-branded coatings apply low-priced, non-UV-resistant polymers and less-efficient pigments. They lack the required flexibility (very high elongation characteristics) to bear the roof’s extreme thermal movement.
- The Result: These coatings start to chalk and yellow in a very short time, losing their reflectivity within a year. They also break and come apart easily when subjected to thermal stress.
Incorrect Film Thickness (DFT)
The coating needs to be applied at a specific thickness to work correctly and last longer. This is known as the Dry Film Thickness (DFT).
- The Technical Failure: To save costs, some applicators thin the paint with excess water or apply fewer coats than required, resulting in a low DFT. A thin film has insufficient material to provide the necessary UV protection and structural integrity.
- The Result: The roof material remains visible, the coating becomes porous, and it provides almost no long-term protection against UV rays, leading to rapid degradation.
Also Read: How Cool Roof Coatings Extend Roof Life
The Solution: COOLROOF®: The Premier HIGH ALBEDO PAINT
To ensure a reflective coating survives India’s punishing climate and delivers long-term cooling benefits, the focus must shift from just ‘reflection’ to durability—a core principle engineered into COOLROOF®.
When you choose COOLROOF®, you are selecting a system specifically formulated to overcome every failure point detailed above:
- Excellent Reflection Towards UV and Heat: The COOLROOF® with the highest SRI (Solar Reflective Index) rating of 122 and solar reflectance of 0.95 effectively rejects the sun’s energy, thus safeguarding the coating from UV degradation and significantly reducing thermal cycling stress. Hence, there won’t be any fast chalking or cracks.
- Rainy Season-Proof, Anti-Blistering Technology: COOLROOF® is a waterproofing covering that has been certified to prevent any water infiltration; thus, during heavy rain, there will be no loss of glue, no blisters, cracks, or peeling. Moreover, it is resistant to fungus, thus your roof will remain clean and its reflectivity high even in the wettest months.
- Unmatched Durability and Adhesion: The product COOLROOF® is formulated with specially developed acrylic resins to give it a very high adhesion strength. It can also resist abrasion of the highest degree. The result is a product that can take the constant heating and cooling of the roof slab and still not get easily punctured in the process.
- Certified Quality with Expert Application: This is a product that has Indian Green Building Council (IGBC Green Pro Certified) and GRIHA approval, meaning you are getting a safe and high-quality coating. Most importantly, we do not let the application errors, the primary reason for coating failures, occur. Our installation teams consist of professional and company-trained personnel who handle the application exclusively. Each team ensures perfect surface preparation and the right film thickness (DFT) every time, which in turn means that maximum product performance and longevity are guaranteed.
