Homeowners, investors, planners and Co. usually agree on what the facade should look like in the finished state. On the other hand, the requirements for and function of the coating material are rather rare.
For example, an ETICS made of EPS with a dark color coating and a light reference value (HBW) is exposed to 20 increased risks:
- In order to avoid damage due to high temperatures, an HBW 20 is required in the regulations. This value is the degree of reflection of a specific color between black point 0 and white point 100. It indicates how far the desired color is from the black or white point. So the darker the color, the more the coated surface heats up and transfers the heat to the EPS panel. When the critical temperature of 70 ° C is reached, the plate can “glaze” and thus deform and crack.
To prevent damage or defects in the form of cracks, there are practical options:
- The easiest is to choose a color that is above a HBW of 20.
- If the desired color is not included, another insulating material can be used in the coated areas, e.g. mineral wool, soft wood fiber or other non-melting insulating materials.
- Also a double reinforcement with a double fabric insert and thus a multi-mass principle, but also organic reinforcements create security.
One hears more and more of so-called "cool colors", "cool pigment colors" and TSR values. What exactly does that mean?
- These coatings are intended to help ensure that the surface does not heat up so much in dark colors and that the sunlight is better reflected.
- The TSR value (Total Solar Reflectance) provides information about how high the reflectance of the coated surface is. The higher the value, the lower the temperature rise on the surface. A TSR reflection of 25% is considered to be thermally safe.
In order to do justice to the function of the coating and the requirements of dark colors on an ETICS and to prevent cracks, the type and properties of the insulation materials and the coating should be checked very carefully in advance (DIN 55699).