CovaSeal 20

A reflective waterproofing roof coating combines two technical mechanisms on the same substrate.

• Solar reflectance sends back up to 90% of radiation rather than letting it penetrate the building. CovaSeal 20 has a new SRI of 107, which delivers an immediate reflective effect from the very first application.
• After drying, the elastomeric resin forms a continuous, flexible, and waterproof film that stays bonded to the substrate during thermal expansion. This is what allows CovaSeal 20 to fill micro-cracks up to 2 mm and hold up on areas where water stagnates.

The anti-UV Top Coat completes the system. It protects the resin from ultraviolet rays, stabilizes whiteness, and prevents chalking over 20 years.

CovaSeal 20 is the reflective waterproofing roof coating suited to the following situations:

• Localized micro-cracks or blistering on the existing waterproofing
• Spot infiltration areas without widespread failure
• Aging bituminous waterproofing, installed more than a year ago
• Old EPDM or PVC membranes, more than ten years old
• Flat or low-slope roofs where water tends to stagnate

For a sound roof that only needs the reflective effect, the pure reflective coating CovaTherm is the better fit. On the other hand, for an out-of-date roof with massive infiltration and detached sheets, a full overhaul has to come first.

A professional reflective waterproofing roof coating, installed, runs on average between €20 and €25 per square meter, all-inclusive: assessment, substrate prep, supply, and application. Three things move the final figure:

• The surface area to coat, with volume discounts beyond 2,000 m²
• The condition of the substrate — a badly degraded one may need spot repairs or a reinforcement fleece
• The complexity of the roof (upstands, drains, penetrations)

Compared with traditional alternatives, the gap is clear-cut:

• New bituminous membrane: €80 to €100 / m²
• Insulation + waterproofing replacement: about €150 / m²
• CovaSeal 20 (2-in-1 reflective waterproofing roof coating): €20 to €25 / m²

CovaSeal 20 cuts the renovation budget by 4 to 7 times, and throws in the reflective effect and a 20-year warranty. You can estimate the savings of a reflective waterproofing roof coating on your building.

A reflective waterproofing roof coating goes on in five controlled steps, carried out by trained professional applicators.

1. Technical assessment. A technician evaluates the condition of the substrate, measures moisture, locates micro-cracks and water-retention areas, and checks material compatibility. Get the assessment wrong and the coating blisters or fails to waterproof.
2. High-pressure cleaning. The roof is cleared of moss, dust, and residue with a high-pressure cleaner, without stripping. This step is what makes the coating bond for the long haul.
3. Base Coat application. The waterproofing layer is sprayed on from the ground, at a rate of 2 to 3 kg/m². The machines stay at the foot of the building, only the hoses go up onto the roof.
4. Optional reinforcement fleece. On sensitive areas (penetrations, upstands, joints), a polyester fleece is embedded in the resin to double the mechanical hold.
5. Top Coat application. The anti-UV finish seals the system and guarantees reflectivity over two decades.

The application is carried out in dry weather, between 10 and 35 °C. A typical 1,000 m² application is completed in 3 to 5 days, with no downtime for the building.

On a conventional dark roof, the surface can hit 80°C at the height of summer. That heat speeds up membrane aging three ways: it absorbs ultraviolet rays, expands the materials, and drives repeated day/night expansion-contraction cycles. Research on the aging of roof coatings is clear that ultraviolet is the main driver of degradation in non-metallic materials, and the process leans heavily on temperature: the wider the daily swings, the faster it ages (Miller, Kriner & Desjarlais, 2002).

By taking the heat out of the roof surface, a reflective waterproofing roof coating sharply limits all three. Field trials run by the Lawrence Berkeley National Laboratory on commercial buildings showed the surface temperature drop from 79°C to 49°C after a reflective coating went on (Akbari, Berdahl, Levinson et al., 2005). Less heat absorbed means less expansion, fewer cracks, and a waterproofing lifespan extended by 8 to 10 years.

Beyond the direct benefits for the building, a reflective waterproofing roof coating helps cut the urban heat island effect — the reason city centers run on average 2 to 10°C hotter than the surrounding countryside. Dark roofs and pavements drive this by soaking up solar radiation and releasing it as heat.

Research on urban cooling shows that adopting reflective roofs across a city can lower the ambient temperature and, with it, the energy demand tied to air conditioning (Santamouris, 2014). One study even estimated that, at the urban scale, rolling out reflective roofs could cut heatwave-related mortality by 18%. Coat an industrial or commercial building with CovaSeal 20 and you join that collective effort while gaining indoor comfort.