The Importance of UV-resistant Air and Moisture Barriers
From the process of evolution from single-cellular organisms to multi-system lifeforms, two things have remained consistent as being the most destructive forces on the planet: water and sunlight. Ironically, the two most destructive forces on Earth are also two essential elements that life needs to exist.
On a cellular level, the UV radiation in sunlight has the potential to break down and fragment the building blocks of life. Water, though crucial for life on Earth, is also destructive enough to wear down mountain ranges and carve entire landforms.
The basic need to create shelter has always taken water and sunlight into consideration. With a better understanding of the physical science behind UV resistance, building materials have come a long way since stone huts and thatched roofs.
Not only is UV radiation destructive to DNA, but it also wreaks havoc on just about any polymer yet created, breaking it down at the molecular level. Within a short time just about any synthetic building material will begin to degrade and significantly lose its efficiency.
Moisture is another destructive culprit as well, since water vapor exists just about everywhere on Earth in some concentration. Moisture gets into small spaces and either due to frost action, or becoming pressurized due to temperature changes, it aids in forcing materials apart. This is basically the same process that, in time, creates valleys in mountain ranges. Moisture also contributes to mold and fungus growth, which can foul the air and even produce lysosomes that will contribute to degrading the integrity of your cladding material.
The key to creating a long lasting air and moisture membrane systems is to eliminate each threat as much as possible. Air permeability can be controlled to improve energy efficiency and maintain air quality, while at the same time allowing for diffusion and the elimination of moisture. With moisture controlled, risk of molds is decreased, as is the possibility for frost-action and destruction of materials through temperature change in the environment.
In the past, it was only a one way street. If you wanted to keep water out, it meant you were also keeping water in. Cladding materials were impermeable. New advances lead to the invention of vapor permeable membranes, which allow interior water vapor (especially from the kitchen and bathroom) to escape via diffusion.
UV radiation will degrade materials in ways with which moisture could never compete. Over time even the most versatile of polymers will break down under the strain of UV. Resistance to UV radiation ensures that the cladding materials are going to withstand UV while allowing controlled amounts of air and moisture to travel (or not travel as the case may be) across membrane systems. A UV resistant water-resistive barrier allows for creative and innovative open cladding architecture. Protection from UV means that cladding materials will not fail before their expectancy.
In just the last 100 years synthetic polymer technology has improved exponentially. Dörken has developed the most advanced air and moisture control products to combat the elements. In spite of these destructive forces, choosing a high performance product and properly installing it will create a durable and high quality building that will stand the test of time