Fenestration with Window Wall Systems

All multifamily buildings require some type of fenestration in the form of windows or other glazed openings. Operable windows in particular are usually required or desired and worked into framed or masonry openings. An alternative for multistory, multifamily buildings can be the use of a window wall system that combines opaque, insulated wall areas with glazed window areas. A window wall differs from a curtain wall in the method of attachment to the structure. Curtain walls typically attach to the building structure and run vertically past the floor plates. Window wall systems can be installed between floor plates, and then additional “slab covers” are installed to create a continuous look along the facade over the edges of the floor slabs. At least one manufacturer has developed a system that provides spandrel glazing as part of the overall height of the system as a “bypass window” that covers the floor slabs and creates continuity between floors.

The primary benefit of a window wall system is that fenestration and opaque framed areas can be designed and produced together, typically all from the same manufacturer. That means there is no guess work in the coordination of details between different trades since the whole system can be fabricated together under controlled factory conditions with improved quality control. A basic window wall system of this type could include unitized wall system framing, insulated and tempered glass, spandrel glass, metal panels, porcelain panels, and a variety of operable windows and doors, all mounted in the factory ready for shipping and quick erection on the job site. All of the typical design aspects of a building facade can be controlled and specified as well as the performance requirements. High-performance insulated glazing with state-of-the-art thermal breaks are all available to achieve overall glazing U-factors of 0.31 BTU/hr/SqFt/F or better. Acoustics and sound transfer can be addressed with sound ratings of STC 38 or better depending on the type of glass specified.

When considering a window wall system for a multifamily project, it is crucial to identify and work with a manufacturer or fabricator very early in the design process. This way, the design team can retain overall design control but understand and use the most appropriate array of products and services currently available. Since everything is custom fabricated, it is easy to be creative and inventive with the window wall design. However, with some understanding of the fabrication and construction process and details, systems can be optimized, performance criteria can be met, and costs can be properly controlled. This is particularly important when dealing with the inevitable variable conditions across a building facade, such as transitions on to balcony decks, ADA access compliance, penetrations from mechanical and electrical lines or equipment, and window-washing equipment.

Working with a manufacturer/fabricator from the beginning can also bring some specialized design tools to the table in the form of customized computer files that can be incorporated into a CAD- or BIM-based design. That means 3-D renderings and other visual presentations can be more accurate and help identify any design issues or opportunities. It can also provide specific and detailed information related to performance, such as data for an energy model, seismic analysis, or acoustic requirements. It also allows for very accurate cost information to be obtained so that cost estimates can be more accurate and reliable. And in cases where it is needed, it will be fairly straightforward to have full-size mockups or samples readily reviewed during design, rather than waiting until construction.

Photos courtesy of Quest Windows

Project: YARD
Location: Portland
Architect: Skylab Architecture

A custom designed and fabricated window wall system can provide multifamily buildings with a high-performance, fully coordinated solution to the exterior walls.

Door and Access Hardware

Safety and security are fundamental aspects of any building but are particular considerations in multifamily housing situations where a lot of people can be coming and going. Residents want to be able to freely access their buildings and living units but also want to be sure that access is controlled when it comes to non-residents or security in their own dwelling units. These needs usually get translated in terms of door and access hardware that is selected based on the variety of doors and access conditions encountered throughout a building or development.

The range of hardware and access control used in a multifamily facility can be extensive. Common areas may be best served not only by conventional key-and-lock systems but also by electric systems that require a resident to act and give permission before a visitor can enter. Or the resident may use an electronic system tied in with a larger security and surveillance system. Identification of a hierarchy of spaces that different people have access to or are restricted from is also important. Management staff, for example, likely needs access to certain areas that are not intended for residents, such as mechanical or electrical rooms or offices. Residents should have access to places that visitors may be excluded from. Service personnel and delivery services need to be able to access appropriate spaces to carry out their duties but then be excluded from other areas. Individual dwelling units need lockable hardware that is most commonly based on conventional keys, but electronic systems are also possible here. Determining the access control needs becomes a first but critical step before considering what specific hardware and control system is best.

Beyond access control, there is a need for general door hardware too. For example, hinges need to be selected based on commercial or residential door locations, including specialty versions such as continuous stainless steel hinges. In some cases, the hinges may need to be self-closing or the doors need to be equipped with door-closer devices to comply not only with security concerns but also code-based fire containment requirements. Exterior doors will need thresholds and weather stripping to control air infiltration but may also need to be selected to comply with handicapped accessibility requirements. Sliding doors, whether interior or exterior, will require specific hardware suited to their operation. Other miscellaneous or auxiliary hardware and trim also need to be assessed and appropriately selected.

Given the range and intricacies of the different required hardware in a project, it is not surprising to find that architects will rely on a hardware specialist or work directly with a manufacturer or supplier to determine the best choices. In some cases, a multifamily building owner or manager may have a selected manufacturer that they prefer to work with in the interest of standardizing the hardware systems used across one or multiple properties. Most national hardware companies are poised to meet these needs with a full line of architectural door hardware focused on security, functionality, and quality of their products, whether the properties will be turned over to individual ownership or commonly managed and maintained for a prolonged period of time. They can routinely provide not only the design and aesthetic needs envisioned by the architect but also the safety and security desired by the tenant and residents. They also can provide either specification consultation or full specification writing services to ensure full coordination across all hardware choices. This has the added advantage for the owner of a single source of hardware that eliminates any confusion or delays if something needs to be addressed during construction or after the building is occupied.

Josh Hager, president and COO of Hager Companies, comments on the hardware selection process by noting, “Hardware manufacturers appreciate the opportunity to collaborate with architects and other industry professionals to provide a full line of architectural door hardware to meet the aesthetic needs of the project as well as the form, fit, function, and ever important building and life safety codes.” Full collaboration in this regard seems to be most appropriate for multifamily projects.

Photos courtesy of Hager Companies

Safety and security in multifamily housing buildings often relies on quality hardware systems that are fully coordinated and appropriately selected to meet the needs of the design team, the building owner, and the residents.