Window walls provide alternative to curtain walls
May 21, 2008
As major urban centers continue to attract young professionals and aging baby boomers who wish to experience the culture, dining and theater that major cities provide, accommodating living needs has become paramount with designers and developers. The trend in the mid- to high-rise new construction market has skewed toward residential and mixed use applications. The window wall has emerged as a design alternative to conventional curtain wall to meet the market requirements of aesthetics, ventilation, flexibility, cost and speed. People want living spaces to have a residential feel versus that of an office. Window walls can offer design features to meet these expectations such as various ventilating styles from projected casement to sliding windows, as well as terrace and sliding glass doors, all seamlessly integrated in the design.
Curtain walls install in front of the slab, whereas window walls span the slab heights and install between the slabs. This difference has significant influences to the overall cost, schedule, quality and risk to individual project stakeholders. Window walls optimize the cost savings component by offering savings in material, labor to install and caulking for weathering when compared with curtain wall systems. Additional savings come through the elimination of fire-stopping required to insulate gaps at the slab locations created by curtain wall application.
The overall project cycle can be compressed by the installation sequencing of window walls that facilitate the total construction process by allowing the exterior facade of the building to be enclosed by floor versus by elevation. This element also contributes to the overall project savings.
Quality is greatly enhanced, compared to site-built curtain walls because all frames are fabricated, assembled and glazed in the controlled environment of automated manufacturing facilities. The consistency and reliability through a tightly managed process virtually eliminates any variability and significantly reduces risk associated with performance gaps as a result of a site environment. In addition, a window wall is typically a systems application that uses pre-engineered, previously tested and certified fenestration products. The customization occurs in the sub-framing components designed for the specific project as opposed to what amounts to a unique design of the entire fenestration system.
Window walls, like curtain walls, offer high performance with respect to design requirements including air infiltration, water resistance and the ability for the system to meet required design pressures building displacements both vertical and lateral. Unlike curtain walls, window walls enhance sound attenuation by eliminating continuous members that span the building height. Those members might resonate sound that originates at lower levels and emit it through the interior tube of typical curtain walls. Reduced sound transmission adds to the multi-family application advantages.
The benefits of window wall have given rise to the application nationally. It has become an economical alternative to traditional curtain wall and offers optimized cost reduction and project cycle time. It minimizes risk through controlled manufacturing process and repeatable design. It offers superior performance, through versatility and meets the design and aesthetic requirements of the design team as well as the dwelling inhabitants.