Leveraging Building Innovations for Housing Affordability

Leveraging Building Innovations for Housing Affordability

Highlights

• Innovations in building materials may lower construction costs by eliminating unnecessary materials, substituting less expensive materials, or streamlining processes. These savings, if passed on to buyers and renters, can make housing more affordable.
• Energy-efficient upgrades to the building envelope, appliances, systems, and controls can lower residents’ energy costs, easing pressures on household budgets.
• Lack of awareness, a desire to do things the way they have always been done, concern over costs and potential defects, and limited workforce skills can prevent builders from adopting new materials and technologies, but researchers may be able to help overcome those barriers.

The costs and characteristics of residential construction materials affect a home's affordability, energy efficiency, and durability.

Housing affordability is a pressing concern for both renters and homebuyers throughout the United States. In addition to factors such as land, labor, and financing, the materials used to construct residential buildings affect construction costs, energy performance, and durability and, by extension, the overall affordability of housing. The extent of this impact presents an opportunity for researchers and policymakers to create innovative materials, technologies, and processes that reduce construction and energy costs and improve long-term durability. Evidence and experience suggest that construction costs can be reduced through simplified and more efficient building materials and processes. Innovative products, from new types of insulation to programmable thermostats, can reduce energy costs, which account for a significant portion of household budgets. Finally, durable materials make for healthier and safer homes and reduce the long-term costs associated with maintenance and repairs. Despite these and other apparent benefits, several barriers prevent the wider adoption and diffusion of newer materials and technologies, including the challenges of measuring the cost savings associated with specific products, split incentives, risk aversion, and a lack of training in the installation or use of new materials. Research — and effective communication of that research, particularly when it takes a whole-home view — can play a pivotal role in leveraging construction and energy breakthroughs to make housing more affordable and durable over the long term.

Construction Costs

Builders and consumers have, to varying degrees, adopted cost-saving innovations in building materials and processes, with some in recent years becoming standards or near standards. Depending on how much of these savings in construction costs are passed on to homeowners and renters, these innovations can potentially have a significant impact on affordability, usually without sacrificing quality, energy performance, or durability.

Substituting less expensive materials of the same or better quality as traditional materials can provide significant savings. Examples of such substitutions that have been widely adopted include installing plastic electrical boxes instead of metal ones, using plastic plumbing instead of copper, and using alternative sheathing materials. Plastic electrical boxes are typically at least 10 percent less expensive than metal boxes, with the added benefit of being 20 percent more efficient.1 Oriented strand board (OSB) sheathing materials are less expensive than, and are considered interchangeable with, traditional plywood materials. Advances in OSB production have reduced panel weight by changing the materials used to bind the product and the processes used to make it.2 In some cases, insulated foam board can be substituted for OSB. Although OSB or plywood may be needed for bracing exterior wall corners as well as in the middle of long exterior walls, lighter, less expensive, and more easily cut insulated foam board can be used as exterior wall sheathing. Foam board also offers higher insulating performance than does OSB or plywood.3 Another strategy to reduce construction costs is eliminating unnecessary materials. For example, advances in framing, sometimes referred to as optimum value engineering (OVE), can eliminate unnecessary wood materials without compromising structural integrity and often increasing insulation value. In many cases, studs can be placed at intervals of 24 inches instead of 16 inches, and two-stud corners with drywall clips can replace three-stud corners, reducing lumber costs and leaving room for more insulation.4 A case study comparing two otherwise identical 2,000-square-foot homes found that the costs for materials and installation on the traditionally framed home were twice as high as those for the OVE-framed home. The OVE-framed home also had lower heating and cooling costs.5

Marea Alta in San Leandro, California, a multifamily development built with modular construction, includes 115 rental apartments affordable to households earning 30 to 50 percent of area median income. Photo by Clark Mishler, courtesy of BRIDGE Housing.

Cost savings can also be achieved by reducing construction waste and inefficiency. On average, the construction of a single-family home produces more than two tons of construction waste. Logistical and labor costs and fees related to waste disposal can be expensive, and reductions in the amount of waste can significantly lower those costs. Reuse and recycling of waste materials — potentially onsite, such as turning wood scraps into garden mulch — reduces end waste. Planning and design can also be optimized to reduce inefficiencies and limit waste.6 This principle also applies to prefabricated building materials such as wall panels. Using factory-built wall panels reduces waste on the construction site, and the panels can be designed and scaled to minimize waste in the factory. In a 2009 report, the National Research Council highlighted increased use of “prefabrication, preassembly, modularization, and offsite fabrication techniques and processes” as part of five core recommendations that, it concluded, could result in “breakthrough improvements” in the productivity, efficiency, and competitiveness of the construction industry.7

The use of prefabricated materials can simplify many onsite construction processes, with the potential to cut both labor and materials costs, although there may be an initial need for training in proper use and installation.8 Using engineered trusses and wall panels, for example, can reduce lumber needs by 25 to 35 percent and construction time by 30 to 50 percent for an estimated net cost savings of 16 percent compared with conventional framing practices.9 The potential exists for greater use of prefabrication in multifamily as well as single-family housing. Galante et al. examine offsite production of three- to five-story, wood-framed multifamily housing and find potential construction cost savings of up to 20 percent compared with traditional building methods. Offsite production offers savings through more efficient processes, reduced movement between and within construction sites, and fewer weather-related delays. Offsite assembly also allows for purchasing at greater scale, driving down procurement costs. The researchers estimate that the use of offsite construction can reduce project construction time by as much as 40 to 50 percent because processes can be done simultaneously; for example, foundation work that must be done onsite can take place while building materials are constructed offsite. The reductions in overall project time can translate into a host of savings, including financing costs. Galante et al. emphasize that such savings may be particularly beneficial in the construction of affordable multifamily projects, because the savings can be passed on to residents in the form of lower rents.10 Andrew McCoy, professor of building construction at Virginia Tech, says that in addition to panels, prefabricated “cartridges” — a fully built bathroom or kitchen, for example, are beginning to appear. These cartridges can then be fitted within the structure onsite. The costs of transporting prefabricated materials from the factory to the site and, in some cases, the equipment needed to move materials onsite constitute the primary limiting factors to broader adoption.11

Energy Costs and Performance

Energy costs make up a significant portion of any household’s expenses and may be especially burdensome for low-income households.12 Reductions in energy costs, therefore, may be an important lever for improving overall housing affordability; a more energy-efficient home is a more affordable home. Building materials and technologies can have a significant impact on a home’s energy performance and associated costs. Currently, the residential sector accounts for about one-fourth of total energy consumption in the United States.13 That large share could be reduced through wider implementation of interventions that improve the energy performance of the building envelope (the parts of the house that separate the interior from the exterior, such as the roof, exterior walls, and subfloor), control energy usage more effectively, and increase the efficiency of household appliances. Many improvements to energy performance work hand in hand with efforts to cut construction costs. For example, in many cases, reductions in structural materials leave spaces for other materials with higher insulating value. In other cases, improving energy performance requires a higher upfront investment, but savings from reduced energy consumption accrue to residents over time.

Energy-efficient construction lowers residents’ utility bills, making housing more affordable over the long term.

Widespread adoption of materials that improve energy performance could have a substantial impact. Research by Kneifel and O’Rear estimates that national adoption of the 2012 International Energy Conservation Code, which requires a range of energy-efficient materials and technologies, for a select sample of building types would lead to a 15.2 percent reduction in energy costs over a 10-year period as well as a 19.2 percent reduction in energy consumption, indicating higher energy performance compared with existing building codes. Savings for residences vary geographically based on baseline code comparison and climate zone as well as on unit-specific characteristics such as size.14

A considerable amount of heat can transfer through the building envelope, making it more difficult to keep the home cool when outdoor temperatures rise and to keep the home warm in cold weather. Various materials used to construct the parts of the building envelope — the walls, roof, subfloor, doors, and windows — can reduce this heat transfer, resulting in a more efficient, cost-effective, and comfortable home. Different wall assemblies such as double-stud walls, truss walls, OVE walls, and walls with exterior insulating sheathing, for example, offer varying R-values (a measure of thermal performance) and airtightness. Although the cost effectiveness of a particular assembly depends on the local climate and the cost of labor and materials, several researchers point to conventional wall frames with exterior insulating sheathing as the easiest to construct while offering a relatively inexpensive and high-performing wall assembly.15

A second way to improve residential energy performance is through more effective energy controls. Programmable thermostats, for example, can offer significant consumption reductions and associated savings without compromising comfort, if settings are optimized. Approximately 10 percent of the energy consumed in the United States is controlled by a thermostat, and an increasing portion of households now have programmable thermostats, suggesting the high potential savings that could be leveraged.16 This potential, however, tends to be unrealized, as users often fail to set thermostats effectively and savings fall well short of projected gains.17 Self-programming thermostats have attempted to overcome these problems. For example, a program called ThermoCoach uses sensors to track and model occupancy patterns against heating and cooling needs and then emails residents suggesting three thermostat configurations — high comfort, energy saving, or balanced — that the user can select with one click. In a randomized controlled trial, researchers found that ThermoCoach saved 4.7 percent more energy than a manually programmable thermostat and 12.4 percent more energy than a self-programming or “learning” thermostat alone.18

In addition, more energy-efficient appliances and products can reduce energy costs. For example, water heating accounts for an average of 14 to 18 percent of residential energy use. Installing an energy-efficient water heater, improving insulation around the heater and pipes, and lowering the temperature setting can reduce energy usage and costs.19 A wide range of high-efficiency appliances such as refrigerators, clothes washers and dryers, and dishwashers are available. Another cost-cutting strategy is to exchange traditional incandescent light bulbs for longer-lasting and more efficient compact fluorescent lamps and light emitting diodes (LEDs). Although more efficient lights tend to be more expensive to buy, they are 3 to 25 times longer lasting and use 25 to 80 percent less energy, ultimately saving consumer dollars.20

Double-stud walls allow space for additional and continuous insulation to improve the efficiency of the building envelope. Paul Norton, National Renewable Energy Laboratory

Durability and Resilience

New building materials and technologies, including energy-efficient ones, may affect a building’s durability and resilience. Durability refers to the ability of a building and its materials to maintain their functionality over their expected lifespans, and resilience refers specifically to durability in the face of natural hazards.21 Improved durability benefits both builders and consumers through reduced maintenance and repairs and enhanced long-term functionality, and it can frequently be added without incurring extra costs.22 Wall systems, for example, which are critical to controlling heat transfer in the building envelope and constitute a substantial portion of the material construction costs, can be vulnerable to natural hazards such as wind. Alternatives to the widely used traditional wood-framed construction may offer better hazard resistance for homes, particularly against hurricanes and tornadoes (although wood-framed construction does perform comparatively well in earthquakes). For example, walls made of insulated concrete forms, precast concrete panels, autoclaved aerated concrete, and concrete masonry units (CMUs) all perform better against winds associated with hurricanes and tornadoes and flood than do wood or steel framing (although CMUs do not perform comparatively well in earthquakes).23 Tests by Texas Tech University researchers found that buildings with insulated concrete form walls can withstand winds of up to 250 miles per hour, with the added benefit of reduced susceptibility to fire.24 Autoclaved aerated concrete panels are much lighter than conventional concrete, are one-sixth or less thermally conductive, and can withstand winds of up to 150 miles per hour.25 Construction costs with alternative wall assemblies are likely to be higher compared with traditional wood framing, but the energy costs are likely to be up to 25 percent lower.26 Concrete-based panels represent a small but growing portion of the single-family residential construction market.27

The roof is the section of the building envelope most susceptible to damage from wind-related natural hazards. Because these hazards often include rain, wind damage can be compounded by moisture threats to a compromised roof. Most residential buildings in the United States have roofs covered with asphalt shingles.28 Research has shown that higher-performance shingles such as styrene-butadiene-styrene (SBS) polymer-modified asphalt shingles to be durable and impact resistant to wind and hail. SBS shingles have greater flexibility than traditional shingles. Wind tests conducted by the Insurance Institute for Business & Home Safety show that polymer-modified asphalt shingles consistently outperform traditional oxidized shingles. A secure adhesion of the sealant strip is important for durability and wind resistance. Research shows that the polymer-modified shingles are also better able to reseal and self-heal compared with traditional shingles.29

Foundations are also susceptible to natural hazards, including water damage and earthquakes. Engineers at Stanford University have developed home construction modifications designed to be more resistant to earthquakes even more severe than the Loma Prieta disaster that struck the San Francisco Bay area in 1989. Instead of affixing the house to its foundation, the upper structure rests on “steel-and-plastic sliders” over plates or bowl-shaped dishes that function as seismic isolators, meaning that they isolate the structure of the home from an earthquake’s vibrations. The engineers sought to use inexpensive materials to make the design financially feasible. In addition, they incorporated processes and materials that strengthen the house in what they termed a “unibody” design. A thicker-than-average drywall is glued as well as screwed to the studs of the interior walls, and wire mesh stucco stiffens the exterior. The engineers tested the design on the Large High Performance Outdoor Shake Table at the University of California, San Diego. The home sustained no significant damage after a simulation of a quake of three times the intensity of Loma Prieta.30

Ideally, innovations or modifications that reduce construction costs or enhance energy performance will also be more durable, and vice versa. However, in practice, these goals may be in tension. For example, spacing studs at 24-inch intervals reduces the cost of materials and nets more space for insulation, thereby improving energy efficiency; however, such walls may be less resilient to wind and seismic hazards.31 In other cases, energy performance upgrades such as double-paned windows and concrete wall assemblies do, in fact, make a structure more resilient to hazards.32 In Greensburg, Kansas, a town devastated by a tornado in 2007, builders executed an innovative design to explore and exemplify the potential of materials and techniques to combine energy efficiency and wind resistance. The home features an airtight building envelope, high-performance insulation, a sun-reflecting metal roof, and efficient appliances as well as a prefabricated wood block system to resist high winds. (See “Combining Energy Efficiency and Disaster Mitigation Efforts in Residential Properties.”)33

Barriers to Adoption of New Technologies

Stanford University engineers developed construction modifications such as a unibody design and seismic isolators that make homes
more resilient to earthquakes. Photo courtesy of Eduardo Miranda and Gregory Deierlein, Stanford University

For many reasons, the construction industry tends to be slow to adopt new technologies and materials. Builders are concerned about the costs of adopting new materials — not only the costs of the materials themselves, but also the potential costs involved in training workers, paying for more highly skilled labor, increased construction time, and callbacks related to new materials and innovations that may impact the builders’ bottom line. McCoy says that for builders of multifamily affordable housing, the direct costs of more energy-efficient “green” building are more or less even with traditional building at this point, but green building has more “soft costs,” mostly paying consultants, to ensure the long-term durability of green attributes.34 Along with skepticism of new technologies and practices, builders may also exhibit inertia, a simple tendency to continue doing things as they have always been done.35 Builders are also risk averse, and, as University of Minnesota professor Patrick Huelman points out, many “have been burned a time or two” after being convinced to try something new. Whether because of a defect in the material or a failure to install it properly, an experience involving costly callbacks for repairs would not easily be forgotten.36 Builders who work on a large scale — the scale at which many innovations can be adopted most efficiently — may be especially reluctant to try a new material without a track record of effectiveness and durability. Persuading builders to try something new requires reducing risk as much as possible and showing that adoption can be both beneficial and profitable. Such calculations of cost and risk exist in a context in which builders are already concerned about what they consider excessive fees and regulations, high labor costs, and high land costs.37

Furthermore, builders may not even be aware of new materials and technologies, or research supporting the usefulness or effectiveness of those materials. Huelman says that the onus is on researchers to more effectively communicate their findings to builders to help them understand the benefits of adoption.38 In addition, the workforce training necessary to properly install and maintain these new materials and technologies is lacking, and both the performance and cost savings promised by innovation depend on correct installation. It may also be unclear how — or even if — new products or processes meet code requirements.39

One challenge to the widespread adoption of technologies and materials that improve energy performance is the issue of split incentives. In many cases, the upfront costs associated with an energy performance investment are borne by the builder, but the energy cost savings accrue to the homebuyer over many years after purchase. Theoretically, the cost of the energy-efficient upgrades could be passed on to the buyer in the sale price of the home. This would require that the buyers value the upgrades and, because most home purchases are financed, that appraisers and lenders also value them.40 Builders may need to actively market the durable and energy-efficient attributes to the homebuyer.41 Similarly, in rental housing in which tenants pay for utilities, the owner may have fewer incentives to invest in energy improvements because the benefits from any energy savings would go to their tenants.42 A related challenge is that the costs and potential savings associated with particular innovations may cut across processes that are traditionally spread among several contractors and subcontractors, making it difficult to convince all those involved to adopt something new.43

Another route to wider diffusion of higher-performing energy products, but in a different package, is for builders to “sell” comfort. Builders may find that buyers can be sold on a home’s “comfort” features more readily than its energy performance, and the builders themselves may be more interested in durability than energy efficiency. Yet both goals ultimately could achieve improved energy performance.44

Despite the many challenges, McCoy notes that the diffusion of innovations related to energy efficiency has accelerated in recent years. He says that the chance of a product being widely adopted is highest when it complements another or if it is similar to other products that meet the same energy goal. For example, the popularity of energy-efficient windows complements improvements in heating, ventilation, and air conditioning systems, because upgrades to the latter would largely be lost without also reducing thermal loss through windows. Interest in energy-efficient innovations tends to correspond with energy prices; when prices go up, consumers become more concerned about the energy performance of their homes.45

Looking Forward

Innovations in building materials, technologies, and processes have tremendous potential to affect housing affordability through reduced construction and energy costs and improved durability. Realizing that potential, however, depends on several factors, including the diffusion and adoption of effective innovations, proper installation and implementation, and careful attention to how they interact with one another. Research — and effective dissemination of that research — can play an important role. Huelman notes that currently little funding is being devoted to research on building materials, and much of it is very narrow in scope and often sponsored by the manufacturers. Such narrow research may be able to show that one material is better than another, but it fails to examine whole systems and the interactions of materials therein. Although funding was historically available, McCoy agrees that since the Great Recession, funding has been lacking for national studies, and he notes that the fragmentation of research reflects the fragmentation of the industry. It is rare, he says, to see research that scales up to support universal and marketable conclusions.46 Further, says Huelman, just having the research is not enough; it also needs to be communicated effectively throughout the industry in a way that gives builders the confidence to adopt new materials and methods.47

With the United States facing a growing housing affordability crisis — nearly 40 million households spent more than 30 percent of their income on housing in 2014 — multifaceted solutions are required.48 Reductions in construction and energy costs may be an important aspect of broader efforts to make housing more affordable. Supported by robust research and evaluation, innovations in building materials, technologies, and processes hold great potential to help achieve those reductions, making housing not only more affordable but also safer and more comfortable, durable, and resilient.

1. U.S. Department of Housing and Urban Develop­ment, Community Planning and Development, Office of Affordable Housing Programs. 1994. “Cost-Saving Construction Opportunities and the HOME Program: Making the Most of HOME Funds,” 7, 13.
2. John I. Zerbe, Zhiyong Cai, George B. Harpole. 2015. “An Evolutionary History of Oriented Strandboard (OSB).” U. S. Department of Agriculture, 1.
3. U.S. Department of Energy. “Where to Insulate in a Home” (energy.gov/energysaver/where-insulate-home). Accessed 10 May 2017.
4. Jan Kosny, Andi Asiz, Ian Smith, Som Shrestha, and Ali Fallahi. 2014. “A review of high R-value wood framed and composite wood wall technologies using advanced insulation techniques,” Energy and Buildings 72, 443; 448; 458.
5. The Partnership for Advancing Technology in Hous­ing. n.d. “Advanced Framing Techniques,” ToolBase TechSpecs, 2.
6. Joseph Laquatra and Mark Pierce. 2014. “Waste Management at the Residential Construction Site,” Cityscape: A Journal of Policy Development and Research 16:1, 313–5.
7. National Research Council. 2009. Advancing the Com­petitiveness and Efficiency of the U.S. Construction Industry, The National Academies Press, 5, 32.
8. Ibid., 32.
9. Miki Cook and Doug Garrett. 2014. Green Home Build­ing: Money-Saving Strategies for an Affordable, Healthy, High-Performance Home, New Society Publishers, 113.
10. Carol Galante, Sara Draper-Zivetz, and Allie Stein. 2017. “Building Affordability by Building Affordably: Exploring the Benefits, Barriers, and Breakthroughs Needed to Scale Off-Site Multifamily Construction,” U.C. Berkeley Terner Center for Housing Innovation, 3; 5–7.
11. Interview with Andrew McCoy, 29 March 2017.
12. Ariel Drehobl and Lauren Ross. 2016. “Lifting the High Energy Burden in America’s Largest Cities: How Energy Efficiency Can Improve Low Income and Underserved Communities,” American Council for an Energy-Efficient Economy, 3.
13. American Council for an Energy-Efficient Economy. “Residential Sector: Homes & Appliances” (aceee.org/sector/residential). Accessed 10 May 2017.
14. Joshua Kneifel and Eric O’Rear. 2015. “Benefits and Costs of Energy Standard Adoption for New Residen­tial Buildings: National Summary,” U.S. Department of Commerce, National Institute of Standards and Technology, XX.
15. Kosny et al., 72, 441–8, 454.
16. Devika Pisharoty, Rayoung Yang, Mark W. Newman, and Kamin Whitehouse. 2015. “ThermoCoach: Reducing Home Energy Consumption with Personal­ized Thermostat Recommendations,” Association for Computing Machinery, 201; Alan Meier, Cecilia Aragon, Becky Hurwitz, Dhawal Mujumdar, Daniel Perry, Therese Peffer, and Marco Pritoni. 2010. “How People Actually Use Thermostats,” 2-195.
17. Todd Malinick, Nate Wilairat, Jennifer Holmes, Lisa Perry, and William Ware. 2012. “Destined to Disap­point: Programmable Thermostat Savings are Only as Good as the Assumptions about Their Operating Characteristics,” 7-163.
18. Pisharoty et al.
19. U.S. Department of Energy. “New Infographic and Projects to Keep Your Energy Bills Out of Hot Water” (energy.gov/articles/new-infographic-and-projects-keep-your-energy-bills-out-hot-water). Accessed 30 March 2017.
20. U.S. Department of Energy. “How Energy-Efficient Light Bulbs Compare with Traditional Incandescents” (energy.gov/energysaver/how-energy-efficient-light-bulbs-compare-traditional-incandescents). Accessed 30 March 2017.
21. Newport Partners and ARES Consulting. 2015. Durability By Design, 2nd Edition, U.S. Department of Housing and Urban Development, Office of Policy Development and Research, 1, 124.
22. Ibid., 2.
23. Ali Memari, Ryan Solnosky, Jacob Tufano, and Micah Dillen. 2014. “Comparative Study on Multi-hazard Re­sistance and Embodied Energy of Different Residen­tial Building Wall Systems,” Journal of Civil Engineering and Architectural Research 1:6, 368–9; 384.
24. Federal Emergency Management Agency. 2008. “Insulated Concrete Forms, Other Measures, Make Home Disaster Resistant,” U.S. Department of Home­land Security.
25. Rutgers Center for Green Building. 2014. “Barriers to Greater Penetration of Energy Efficient Wall Assem­blies in the United States Housing Market,” 8–9, 19.
26. U.S. Department of Housing and Urban Develop­ment. 2001. “Costs and Benefits of Insulating Con­crete Forms for Residential Construction,” 5, 14.
27. Rutgers Center for Green Building, 10–1.
28. Newport Partners and ARES Consulting, 115, 117.
29. Heather Estes and Ian M. Giammanco. 2016. “Du­rability of Polymer Modified Asphalt Shingles,” 1–2; Insurance Institute for Business & Home Safety. 2014. “Relative Impact Resistance of Asphalt Shingles: Sum­mary of UL 2218 Impact Tests.”
30. Amber Dance. 2014. “Stanford engineers build, test earthquake-resistant house,” Stanford University.
31. Federal Emergency Management Agency. 2010. “Natural Hazards and Sustainability for Residential Buildings,” U.S. Department of Homeland Security, 2-5.
32. Center for Housing Policy. n.d. “Linking Efforts to Improve Disaster Resistance and Energy Efficiency of Homes.”
33. U.S. Department of Energy. 2013. “Building Green in Greensburg: Meadowlark House.”
34. Interview with Andrew McCoy.
35. Interview with Pat Huelman, 28 March 2017.
36. Ibid.
37. Interview with Andrew McCoy.
38. Interview with Pat Huelman.
39. Rutgers Center for Green Building, 5.
40. Alliance Commission on National Energy Efficiency Policy. 2013. “Residential & Commercial Buildings,” Alliance to Save Energy, 13, 32; U.S. Department of Housing and Urban Development, Office of Policy Development and Research. “Measuring the Savings of Green Building Technologies: A Selection of Promising High-ROI Green Building Technologies for Builders,” 3.
41. Newport Partners and ARES Consulting, 7.
42. Alliance Commission on National Energy Efficiency Policy, 13.
43. Ibid., 18.
44. Interview with Pat Huelman.
45. Interview with Andrew McCoy.
46. Ibid.
47. Interview with Pat Huelman.
48. Joint Center for Housing Studies of Harvard Univer­sity. 2016. “The State of the Nation’s Housing,” 31.

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