The Modernization of Multifamily Housing

Providing luxury living without sacrificing affordability

By Peter J. Arsenault, FAIA, NCARB, LEED AP

According to data from the federal government, the number and type of multifamily projects completed annually has changed between 2012 and 2016. The Survey of Market Absorption of New Multifamily Units (SOMA), sponsored by the Department of Housing and Urban Development (HUD), is a free and regularly updated reporting source that uses the U.S. Census Bureau’s Survey of Construction (SOC) as its sampling base. Each month, a sample of residential buildings containing five or more units is selected for SOMA. Its data for the years 2012 through 2015 shows that the number of completed multifamily housing units increased notably in each of those years. In 2016, the total number dipped a bit lower than 2015 but was still higher than all of the years between 2012 and 2014. During this same time period, the mix of different types of multifamily housing also showed notable changes each year, particularly with fewer subsidized or tax-credit units being constructed.

The SOMA is based on an initial three-month interview that collects information on amenities, rent or sales price levels, number of units, and type of building, including senior housing. It also tracks the number of units taken off the market (i.e., absorbed) by virtue of being rented or otherwise occupied. Hence, it can track the rate of absorption of new apartments as an indicator of supply and demand of multifamily housing in areas around the United States. Reports of this data for the entire country are broken down for specific metropolitan areas, published quarterly, and released on the Internet (www.census.gov/housing/soma). The latest data is generally available in early March, June, September, and December. There are also two annual online publications, the H-130 Annual, which provides 12-month absorption data for the previous year and is released the first week April, and the H-131 Characteristics of Apartments Report, which provides annual three-month absorption rates, released the first week of July. In reviewing the annual data between 2012 and 2016, it is clear that there are regular cycles of units becoming available and being absorbed. While the general numbers may be up, the rate of absorption appears to have slowed such that more units are still available 90 days after first coming on the market than previously.

The trends observed from this SOMA data suggest a few things. While the current number of new units may be slowing a bit to let the absorption rate catch up, the market overall is still strong. The availability of units also suggests that competition is strong, meaning that owners and developers are looking for ways to differentiate themselves from other available options in any given market. That is evident in the many projects that offer more attractive designs and luxury options to lure new residents, all while keeping costs under control, of course.

With all of the above in mind, we will look at five different but significant architectural building systems related to the design and construction of multifamily housing. Each one will be examined based on the ways it can be used to provide better design, control construction costs, and provide residents with an attractive, comfortable, and desirable housing option.

Structural System Choices

Every multistory project brings unique structural design challenges, and that is quite true for multifamily buildings too. Yet they all share the need to balance architectural design intent with cost-effective construction systems. Visual issues come into play by deciding to use a building system that is either covered over or is left exposed as part of the design aesthetic. Space planning and optimization can be impacted directly based on the cost-effective spans of structural systems that can limit locations of structural walls and columns. Cost control is always on the mind of the building owners or developers, meaning that they need to rely on the design team to justify the structural system in terms of cost effectiveness when compared to other systems. Clearly, the structural system, architectural design, and overall cost are all intertwined and related to each other. The ideal situation is to select a system that allows for structural synergies and economies of construction to enhance the architectural design.

The common structural systems used in multistory construction are based on either concrete or steel, a combination of the two, or even combinations with wood in some cases. The selection is typically determined by the specific criteria and needs of a given project not only for structural strength but also for fire safety, sound separation, and coordination with other building systems and finishes. One approach that seems to meet all of these needs fairly economically is a “thin-slab” composite floor system. Fundamentally, this hybrid system is based on using steel decks and poured concrete acting together to create a long-span floor that requires fewer intermediate supports. As such, it can also mean that the floor-to-floor heights may be able to be reduced since the structure spanning between load-bearing walls or beams is only comprised of the composite slab without the use of additional joists, trusses, or girders. For example, a long-span composite floor system can achieve open bays up to 1,200 square feet, with clear wall-to-wall spans up to 36 feet without support columns. For longer spans, a support column can be thinned to half the size of equivalent reinforced-concrete columns.

In some cases, thin-slab construction may mean an additional story can be achieved using a long-span composite floor system compared to a conventional steel or reinforced concrete structure. An added story means more income for a building owner and may improve the overall project financial picture considerably. Thin-slab floor and roof designs also align with LEED v4 because they support a holistic, long-term view of project performance and costs, both to the building owner and to the environment.

Of course, there is no single solution for all buildings or even throughout a single building. For example, the most cost-effective and best-performing design solution may be a mix of structural systems, such as a roof made up of a traditional steel joist and deck system, occupied floors constructed from a long-span composite floor system, and outdoor canopies and sun screens made from exposed architectural steel deck. The best way for an architectural and engineering design team to get up-to-date information on capabilities and cost is to work with a steel system supplier in the earliest design stages. By using their assistance, more informed design and budget decisions can be made in the selection of a steel building system that will not only excel in the area of design intent but also holistically take into account a set of related material costs, erection costs, and effects on project timelines. Therefore, getting the right information early on allows design teams to quickly and effectively determine which system or systems make the most sense for any particular project.

David Abernethy, MSR market development manager at New Millennium Building Systems, sums it up this way: “New design ideas require a knowledge of steel building system options and the ways you can integrate them into specific projects. As design teams are challenged to be ever more mindful of the ‘embedded’ costs that can come with more traditional building systems, they will look for ways to overcome those costs by taking advantage of a given building’s structural synergies.”

Brick Masonry

Many multifamily housing projects incorporate brick masonry into the design of exterior and interior walls. The reasons for its use often include durability, aesthetic appeal, and marketability of the project. From a design standpoint, it also offers a wide and diversified variety of types, colors, and shapes that provide architects with a lot of choices and design flexibility. Some of the commonly available choices include the following:

• Extruded brick: Many building materials are created using the process of extrusion, and that technology has become a part of brick masonry production too. This means that brick can be produced efficiently and economically, while still providing the requisite versatility, strength, and value for multifamily projects. Extruded brick technology has been advanced by brick manufacturers, making it available in a wide spectrum of colors, a multitude of shapes, and even different textures.
  
  
• Glazed brick: While brick has been traditionally thought of in terms of natural, earthen colors, modern brick-making technology allows new options that go beyond conventional color choices. Glazed brick is created by applying a glaze to the outer surface of extruded clay that is carefully fired. Since glazes are available in a virtually unlimited range of colors, the finished, colored look of the brick is equally unlimited. Further, variations in textures are possible with glazed brick from a glossy, glass smooth finish to a mottled, speckled, and rough texture. This range of choices allows brick to be used in dramatic fashion in places where other materials might have been thought of as the only option.
  
  
• Clay-coated brick: In some cases, a matte surface in a defined color spectrum is the preferred choice. Manufacturers can provide this option with a selection of clay-coated brick. From a building performance perspective, the surface of clay-coated brick remains breathable, which can be an important consideration in some wall assemblies. This characteristic allows liquids and vapors to pass in and out without damaging the permeable surface, thus maintaining the classic look of the brick.
  
  
• Molded brick: This traditional method of brick production remains in use to provide individualized brick options. The bricks are typically formed in molds, producing intentionally irregular shapes to provide a different character and appearance to a finished wall. As such, it delivers both large-scale design features and smaller, more intimate touches. Custom molded shapes to achieve unique design details are also available from some manufacturers.
  
  
• Handmade brick: Replicating the centuries-old tradition of brick making craftsmanship, some manufacturers can still provide bricks made by hand to match or create a unique brick character or profile. Such handmade brick is completely customizable using a spectrum of rich colors and shades. The result is a classic style of brickwork that takes advantage of contemporary masonry knowledge and understanding.
  
  
• Thin-brick veneer: Recognizing that there are situations where the look and character of brick masonry is desired but the thickness of conventional brick is problematic, manufacturers have introduced a thin-brick alternative. By providing a thinner and lighter product, sometimes with a coordinated mounting system, manufacturers are providing architects with a modern choice that overcomes other restrictions for interior or exterior walls and design elements. The space-saving and affordability aspects of thin-brick systems mean that real brick surfaces are possible in projects where it previously might not have been considered.

Regardless of the type of brick selected, all of them are available in a variety of sizes, including standard, jumbo, economy, and even custom sizes. Similarly, numerous shapes are readily available for typical building conditions, such as corners, sills, treads, coping, water tables, and others. Color selection and, more typically, blends of colors will vary by manufacturer, so it is important to review availability before finalizing a choice. In that regard, most brick suppliers are quite willing to collaborate with architects on building concepts by providing technical and design support from the earliest stages of design. Ultimately, the selections can be optimized to produce the intended look, meet performance demands, and control costs.

Panelized Cladding Systems

Some multifamily building designs are based on an exterior design aesthetic that uses a lightweight cladding over a framed wall assembly. Commonly, this cladding is used in standard-size panels made from fiber cement, engineered wood, or even thin composite aluminum panels. It might also include siding of different types made from some of the same materials. Designing with such materials is fairly straightforward, but attention needs to be paid to detailing the way the panels are secured to the building and how the edges of the panels are addressed. Typically, some sort of trim has been applied to accomplish this using wood, composite, or plastic-based materials. While those are effective and can be good for some buildings, their width, bulk, and ongoing maintenance can make them less desirable for other designs.

As an alternative to traditional trim, many architects are turning to the use of thin, extruded aluminum trim systems. The use of extruded aluminum in buildings is common due to the versatile nature of the material and its durability in both exterior and interior applications. When used to hold the edges of wall panels, it provides architects with a unique means to detail corners, vertical and horizontal joints, and material transitions. Further, it can be specified in common thicknesses and profiles to suit any of the lightweight cladding materials already mentioned, or even for gypsum board and other exterior or interior panel products.

Used on the exterior, aluminum trim aids architects in creating modern, panel-based facade designs that have become more common across the country, particularly for multifamily projects. It is available in a variety of profiles, some of which create a recessed reveal between cladding panels and others that project outward to accentuate the lines of the design. Used in any of these ways, it has typically been shown to be less expensive with a more elegant look than other options. On building interiors, such as communal spaces in multifamily developments, aluminum trim can be used to create bold corners or wall bases in addition to delineating wall panel patterns.

Of course, the color of the trim is an important design consideration, regardless of the location. There is great flexibility available in this regard too. The trim can be specified as primed only ready to be painted in the field or as prefinished in the factory. The prefinished choices vary by manufacturer but typically include durable powder-coat paint, conventional wet paint coatings, or anodized aluminum in standard colors. In this regard, the trim can appear to blend in with the adjacent panels or cladding, or it can be used to highlight all or some of the visual lines it creates. This flexibility using familiar and long-lasting finish options means that both the design and the performance level can be controlled.

Architects who have used this approach include Russell A. Hruska, AIA, principal and cofounder of Intexure Architects in Houston. He points out that “using extruded aluminum trim between panel joints becomes an architectural element and is a way of expressing the joints and defining their deliberate placement. It adds a level of architectural refinement.” From a performance perspective, he adds, “Aluminum trim, when used with fiber cement panels or lapped siding, is more cost effective than stucco and provides long-term durability while achieving our design aesthetic.” Val Glitsch, FAIA, confirms this experience, indicating, “The alternative to premanufactured aluminum trim is wood, which gives a very different aesthetic, is bulkier, and, for water infiltration concerns, can only be used for vertical joints. The best way to get a quality, consistent, properly installed, and cost-effective result is to use extruded aluminum trim designed for that purpose.”

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.

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.

Conclusion

Multifamily housing remains a big part of the construction market, even though it experiences some ebbs and flows in production and some regional variations. Building owners and residents continue to require quality and even luxury features but at a reasonable cost. Architects and other design team members who can identify the best ways to provide such amenities while controlling costs, including some of the techniques discussed in this course, increase the likelihood for successful projects and repeat work with building owners or developers.

Peter J. Arsenault, FAIA, NCARB, LEED AP, is a practicing architect, green building consultant, continuing education presenter, and prolific author engaged nationwide in advancing building performance through better design. www.linkedin.com/in/pjaarch