The sun emits ultraviolet (UV) light that degrades certain materials over time. As the chemicals are constantly exposed to ultraviolet (UV) radiation from the sun, materials can break-down. The sun’s heat also expands certain materials, which then contact as they start to cool, causing gradual, long-term damage as the cycle repeats.
Solar heat can cause blisters (bubbles of hot and expanding air) discoloration through bleaching, warping and cracks which are vulnerable to leakage.
Synthetic polymers such as plastics, as well as naturally occurring polymer materials such as wood, are extensively used in building construction and other outdoor applications where they are routinely exposed to sunlight. The UV-B content in sunlight is well known to have an adverse effect on the mechanical properties of these materials, limiting their useful life. Most commercial organic-based polymers used in the building and construction undergo photolytic and photo-oxidative reactions during exposure to solar UV radiation. It is common to see a rapid decline in surface, colour and mechanical properties.
Facades with open rainscreen cladding expose more of a building to the effects of UV light. In those cases, a UV resistant membrane is enormously beneficial in protecting the building and maintaining its long-term condition.
As well as providing protection against the harmful effects of solar exposure, a UV resistant membrane should ensure the building envelope has a high level of water repellence – especially in open/ventilated facades and jointed cladding – as well as providing high breathability to help control condensation and keep moisture away from the building’s interior. When a membrane is highly breathable, moisture quickly diffuses from within the building to provide good climatic comfort and to ensure that the building’s structure remains in good condition.
A water tightness rating of W1 is recommended for open facades and high-rise buildings which are more exposed to driving rain. Membranes which offer exceptional imperviousness to both wind and rain will increase the lifetime and effectiveness of the insulation. It is important to choose a membrane that retains all of these performance qualities when exposed to high UV and heat levels. ITP’s membranes UV resistant facade membranes maintain all key performance levels in the face of long-term exposure to solar light and heat.