• Block frame with T-subframe (window replacement). (See Figure 23.) This installation system is typically used when metal windows are being replaced with fiberglass windows.  Like the standard sub-frame, it allows window replacement from inside the building and offers similar labor and cost benefits.  The T-shaped subframe is used to conceal the existing metal window frames, allowing them to be left in place. Unlike the standard sub-frame, however, the new window is installed flush with the face of the T-subframe creating a different profile and shadow line on the building.
  
  

Figure 23: Block frame with T-subframe installation details. Images courtesy of Pella Corporation

Regardless of the type of building and wall construction that is being employed, then, the techniques of installation and attachment of fiberglass windows has progressed to be able to accommodate almost any commercial installation. The number of different methods that have been standardized and simplified, actually offer architects more freedom of design with the rest of the building without compromising performance, construction, or economy.
    
Conclusion

Fiberglass windows are an advanced alternative for commercial buildings of all types. They are designed and manufactured for exceptional energy efficiency and durability, even in extreme weather conditions. They combine the beauty architectural design requires along with the quality construction and outstanding performance commercial projects demand. They are well suited for a variety of different design applications whether horizontal, vertical, or punched window looks are sought. Their installation methods are numerous and suited to a variety of building construction types for both new and existing construction. Regardless of the design intent or installation method used, designing and specifying fiberglass windows into commercial, institutional, and multi-family buildings, yields improved design, better performance, and lasting durability.

 

Peter J. Arsenault, FAIA, NCARB, LEED-AP is an architect and sustainability consultant based in New York State and writes on topics related to sustainable design and practice solutions nationwide. He can be reached at www.linkedin.com/in/pjaarch

Founded in 1925, Pella Corporation offers aluminum-clad wood, wood, fiberglass, and vinyl windows and doors at varying price points to meet the performance and budgetary requirements of virtually any non-residential or residential project. Products are appropriate for both new construction and renovation projects and are often used in punched openings, entrances, storefronts and window wall applications. Registered with the American Institute of Architects as a Continuing Education System provider since 1995, Pella is committed to developing quality learning activities in accordance with AIA/CES and Health/Safety/Welfare (HSW) criteria. Pella offers several continuing education programs through  www.pellacommercial.com in addition to this partnership with Architectural Record. Contact Pella Commercial at: 800-84-PELLA or  www.pellacommercial.com or E-mail: commercial@pella.com.