The Science behind Heat Reflective Render
A famous song once said ‘I want to paint it black’ and for most buildings that have used a black coloured render this is very true.
To gain a truly dark coloured render has always been difficult due to the higher absorption of solar radiation and therefore the excessive warming up of the surface. Naturally the darker the colour the more absorption that will occur and with renders this can lead to thermal cracking, fading and a quickening of the aging process.
So what’s new?
Infrared Reflexion is based upon the ability to reflect different parts of the light spectrum selectively. The light absorbed by the surface is electromagnetic radiation and is made up of Ultra Violet radiation, visible light and the invisible infrared radiation. The latter of these represents 53% of all solar radiation on the surface of the planet.
As the name implies, IR Reflexion has the ability to reflect the infrared part of the light spectrum and by doing so can have a 40% higher Total Solar Reflectance meaning the surface will not warm up as much.
How does this change External Wall Insulation and Renders?
All renders have a light intensity factor, which determines the depth of colour with pure black being at 1 and pure white at 100. With External Wall Insulation systems it has been generally said that you would not use a render with a light intensity factor of below 25, as the thermal gain onto insulation would cause a breakdown in the finish.
With TREND from JUB all this has changed.
The JUB organisation has developed a breakthrough tinting process which incorporates the new technology of IR Reflexion into one of our topcoat renders. This now enables the specification of renders with a light intensity down to 5 with an External Wall Insulation system and with the knowledge that the long-term performance and general product cost is not affected.
With the tangible benefits IR Reflexion, which can reduce the surface temperature of the render by 15 degrees Celsius, there are no more barriers to using dark renders.
The TREND topcoat and can be used on all types of buildings including large areas, south facing facades and will not require any form of paint coat to gain a consistent finish.