Glazed Curtain Wall Systems
In a general sense, the term “curtain wall” refers to an exterior wall that does not support loads other than its own weight. Curtain walls are therefore non-structural and serve solely to protect the building from the elements. Curtain walls are typically exterior walls that do not carry floor or roof loads, according to the Whole Building Design Guide. Wind loads and the curtain wall’s gravity loads are transferred back to the structural support of the building, and are typically thin, aluminum framed with glass panels or thin stone panels that “hang” like a curtain from the build’s structural element. A typical glazed curtain wall system is often a metal frame (usually aluminum) with in-fills, which can be glass, brick veneer, metal panels, thin stone or precast concrete.
5 Common Problems & Solutions
- Water and Air Infiltration – Water intrusion causes interior damage and can promote biological growth. To resolve water infiltration, water testing is essential to understand the source and to confirm repair and performance. Seal failures can often result in air infiltration, which can cause condensation on window frames resulting in water damage and energy loss.
- Aluminum Coating Failure – When finishes are properly applied, they are high performance and can last in excess of 20 years. However, coatings can prematurely fail due to application issues. To resolve applied finish issues, glazing survey, samples, and laboratory testing is often needed.
- Insulated Glazing Unit (IGU) Failure – Most modern exterior glazing consists of dual or triple paned glass. The air gap between panes is sealed with inert dry air with desiccants to soak up moisture. Dual silicone and PIB
- Common Problems & Solutions sealants are used to keep air and moisture out. Failure of these seals can result in IGU failure causing fogging and corrosion of Low-e silver coatings.
- Traffic Noise – Retrofitting the glazing with laminated glass is a noise reducing solution, and provides a 99% UV screen.
- Condensation – When the temperature of the glass or aluminum frame in the curtain wall reaches a dew point temperature on the interior space, condensation occurs. Basic design, such as thermal breaks and insulated glass, can prevent this. Failures can result from unintended thermal bridges and air leakage.