For commercial construction projects, curtain walls are an attractive option. They allow for a wide range of glass sizes and shapes, offering architects the opportunity to create unique building exteriors. However, curtain wall construction presents some unique challenges. It must be able to resist sudden water intake and gradual wear, while also transferring forces back to the primary building structure and providing fire, smoke, and acoustic separation. In addition, it must account for thermal expansion in any included materials.

Curtain wall systems are generally classified as either stick or unitized. In a stick system, a frame (mullions) is installed and then glass or opaque panels are located and installed within the frame. In a unitized system, the curtain wall is prefabricated off site in large units and then erected on the building. This allows for quicker installation and also reduces onsite labor costs.

From Blueprint to Brilliance: Demystifying Curtain Wall Construction Techniques

The design of a curtain wall starts long before the glazier ever gets to the job site. The architect and general contractor must establish control lines to determine where the stick wall is going, which is done using the same procedure used to lay out floors for a building. These are known as control line drawings, and must be reviewed and double-checked by more than one person.

Once these control lines are established, the next step is to ensure that the curtain wall is designed to withstand the forces it will be subject to. This includes reversing lateral wind pressures that are induced by the building envelopment, resisting sway induced by a seismic load or by the dead-load weight of the curtain wall itself, and preventing water penetration through the outer seals.