Curtain walls offer architects a huge range of freedom in building aesthetics. They allow the use of different materials, including aluminum and single or double glass. The spandrel areas are also a good place to play with geometry and bring architectural creativity to the project. They can also be designed to hide the floor beams and other supporting elements of the building structure.

The key requirements for curtain walls are a high degree of structural performance and visual design flexibility. There are a few basic systems that can be used: Stick (modular) or ladder (stick and clip type). Stick system mullions are fabricated in the shop and installed and glazed on the jobsite. Ladder system mullions are split and either snapped or screwed together with a half box and plate. This allows sections of the mullion to be fabricated in the shop and assembled on the jobsite and can reduce installation time. The tradeoff is reduced structural performance.

Unlocking the Beauty and Functionality of Curtain Walls: A Comprehensive Guide

Other key criteria are thermal performance, water diversion, seismic response, and maintenance requirements. Thermally, curtain wall performance is a function of the glazing infill panel, frame construction behind opaque (spandrel) area, and perimeter details. It is important to avoid exposing thermally conductive aluminum frames to cold air. A good solution is the use of a thermally broken aluminum frame.

Designers need to consider the thermal performance of a curtain wall early in the design process. This is done by modeling the building with software and taking into account the wintertime interior air temperatures. It is also recommended that a field mock-up of the curtain wall be constructed and tested to verify that it will perform as designed. This is best scheduled prior to the release of the curtain wall shop drawings.