CovaTherm Light

A solar-control coating works by selective filtration of the solar spectrum. It lets visible light through, which is responsible for the natural light input, and blocks two specific wavelengths that degrade comfort and materials:

• Ultraviolet (UV) rays, which heat imperceptibly but degrade the molecular structure of polycarbonate (yellowing, embrittlement) and cause eye strain in humans.
• Infrared rays, responsible for nearly all of the radiant heat felt by people located under the skylights.

By blocking these two bands while letting the visible spectrum through, CovaTherm Light transforms the indoor experience without depriving the building of its natural light. So the substrate keeps what makes it useful (free daylight, savings on artificial lighting) without the drawbacks (radiant heat, glare, accelerated degradation).

CovaTherm Light is the UV-protective coating for polycarbonate suited to the following situations:

• Workstations under skylights that are uncomfortable in summer, with recurring complaints from teams about heat or glare
• Aging polycarbonate or polyester barrel-vault rooflights or dome skylights that are visibly yellowing or degrading
• Workshops, production halls, warehouses with a significant share of translucent roof surface (from 20 to 25%)
• Commercial buildings fitted with light wells that create localized overheating zones
• Stores and showrooms where glare disrupts the reading of labels, screens or displayed products

For an opaque roof with no translucent elements, the CovaTherm reflective roof coating remains the solution. For glass or glass-roof surfaces, a bonded interior solar film is a better fit.

The price of a professional UV-protective coating for polycarbonate, installed, depends mainly on the accessibility of the skylights, their geometry (flat, curved, vaulted) and their condition before application. The price per m² is not public; it is calculated by quote based on the access constraints and the geometry of the translucent elements.

Next to the usual alternatives, CovaTherm Light costs a fraction of the price:

• Replacing the skylights with new anti-UV models: several hundred euros per m², including dismantling, removal and refitting in line with roof waterproofing standards
• Bonded interior solar film: suited to glazing, but tricky to install on curved polymers and not very durable over time
• Motorized interior blinds: a partial solution that removes light as well as heat

You can estimate the savings of a solar-control coating on your building in a few minutes.

A CovaTherm Light project unfolds in four controlled steps, carried out by a professional applicator following our application instructions.

1. Technical diagnosis. A technician assesses the condition of the skylights, measures their residual translucency, checks their load-bearing capacity and identifies the most degraded areas. Some heavily yellowed barrel-vault rooflights may require prior replacement rather than a simple treatment.
2. Preliminary cleaning. The translucent surfaces are cleared of moss, dust and organic deposits that impair light transmission, then rinsed with clean water.
3. Application by roller or airless sprayer. The acrylic coating is applied in thin, even coats, from a technical gangway or an aerial work platform depending on the configuration. Two cross passes ensure uniform coverage with no runs.
4. Drying and finishing rinse. A post-drying rinse removes any residue along the edges and stabilizes the final adhesion.

Application is done in dry weather, at moderate temperatures. A typical project is completed in 1 to 3 days depending on the skylight area, with no downtime for the building. We give your installer the safe-working instructions for translucent surfaces and the dosage parameters specific to the product.

Polycarbonate, the predominant material in modern skylights, is particularly sensitive to ultraviolet radiation. Exposed without protection, it undergoes a documented physico-chemical degradation process: progressive yellowing, loss of transparency, the appearance of surface microcracks and a decline in mechanical properties (Redjala et al., 2020). A study conducted on UV-additive and UV+IR-additive polycarbonate skylights showed that the yellowing index can go from near-zero values to significant levels over a period of 21 months of natural exposure, with direct consequences for light transmission and impact resistance (Bakırcı & Kahveci, 2025).

By filtering UV at the source before it reaches the polycarbonate, CovaTherm Light drastically slows this process. Your skylights keep their optical and mechanical properties longer, which pushes back the replacement bill by several years.

In workshops and commercial halls fitted with skylights, the radiant heat under light wells is not a trivial discomfort: it leads to a documented drop in concentration, accelerated fatigue and physical symptoms (headaches, dizziness, hot flushes) that degrade both productivity and quality of life at work. Research on reflective roofing strategies also shows that better indoor thermal comfort, even without air conditioning, has a measurable effect on occupant well-being and on the building’s energy demand (Santamouris, 2014). So treating the translucent elements of a roof is also an investment in working conditions, not just in energy efficiency.