Viroc tests the resistance of ventilated façade panels after 11 years of exposure

The façade of a building it the part of the structure that usually is subjected to the most deterioration, owing to natural weathering from exposure to UV rays, temperature oscillations, the rain and the wind. This is why we often see restoration and renovation work on façades, which are essential to keep them well maintained. In this article we will discuss the benefits of including Viroc in façade projects, as well as analysing their mechanical features after 11 years of exposure to the natural elements.

Viroc panels are an excellent material for façades, enhancing the aesthetics, durability and thermal comfort of buildings. For example, the ventilated façade system reduces the quantity of heat that buildings absorb as they shade the wall of the building, thus reducing energy costs.

In addition to the technical and installation factors, the aesthetics and the colours of a panel also influences the deterioration of a façade and the consequent energy efficiency.

  • A façade with dark colours absorbs between 70% and 90% of solar energy. This gain in heat can lead to the thermal expansion of the materials and the emergence of cracks.
  • Brightly coloured façades tend to attract more dirt, which stimulates the growth of microorganisms around the building, leading to deterioration.

Cernusco Sul Naviglio School

Buck Mountain House

After 11 years, what condition are the Viroc panels in?

On 26 October 2022, two grey Viroc panels were disassembled which were part of a ventilated façade in Setúbal. The panels had been installed in July 2011, and had been exposed to weathering for the last 11 years.

It is pointed out that the Viroc panels had been installed on the façade raw, without any varnish or paint finish.

After disassembling the panels, samples were cut to test their current physical-mechanical properties. The results obtained were compared with the properties required by the standard and the test results from the production date.

The tests were carried out by the Viroc Laboratory, in line with the EN 634-2 standard for Cement Bonded Particleboard.

The average values of the tests are shown in the table below.

It was found that after 11 years of exposure to weathering, the panels did not show signs of deterioration. Analysis of the physical-mechanical properties showed significant improvements owing to the carbonation of the cement.

To sum up, there was a 10% rise in the resistance to bending, a 40% increase in the modulus of elasticity and a 22% rise in traction resistance. The density fell slightly (-2%) and the moisture of the panel was lower, indicating that the panel dried over time but maintained its moisture level within the ideal interval.

Panel finish

Throughout the construction process with Viroc panels, it is important to take special care in the preparation of the surface, finish and installation.

The Viroc panels are supplied raw, with no finish. The surfaces contain some irregularities and imperfections, such as small incrustations, marks, scratches and salts deriving from the chemical reactions. Therefore, a varnish or paint finish is recommended for the Viroc panel, to protect it and make it easier to clean and maintain.

  • When the panel is installed in a visible location, the surface should be cleaned/polished to remove dust, scratches, dirt and salts.
  • Before applying the finish, the panels should be cleaned to remove any dust that will reduce the efficacy of the finish. Read about the recommended finishes for Viroc.

For any further questions about the application of Viroc panels, we recommend reading the technical application dossier.

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