Chapter 2: Literature Review
Early Planning Literature Review:
Throughout the 1970’s and 1980’s increased academic interest in “Accessory Apartments” began to appear. Numerous articles were published in planning journals and various experts emerged in support of expanding the capacity of single-family homes (Gellen, 1986, Hare, 1982, Moudon, 1982). Planners emphasized the wasteful use of collective resources including: land, transportation infrastructure, housing infrastructure, utilities, and energy use in low density, single-family neighborhoods. Many planners identified enormous potential for conversion apartment development within the single-family neighborhood (Moudon, 1982). A conversion apartment refers to using un-utilized space in a single family house to build an additional apartment. Two prominent researchers, Patrick Hare and Martin Gellen, published numerous articles and books about the potential for conversion apartments to expand the housing stock without adding new structures (Gellen, 1986). Low density, single-family neighborhoods are still “...the most adaptable physical form of housing in America” (Hickey, 2010).
Conversion apartments and small structure dwellings are now commonly recognized in various cities’ zoning code as Accessory Dwelling Units (ADUs). ADU regulations have been making incremental steps toward convergence between citizen practices and municipalities policy for the last several decades. Presently there is a small body of literature available focusing on Accessory Dwelling Units (ADUs). The 70’s and 80’s planning literature was much more general, today the literature focuses on the idiosyncrasies of a particular locale. The experiences of various cities acted as the guiding principles of the research.
Context: Cities of Interest
Portland, Oregon:
Portland has a long history with Accessory Structures and Accessory Dwelling Units. The City of Portland has remained an innovator of progressive ADU policy and has seen significant results with unique and creative dwelling units. The structures utilize a variety of “...recycled and renewable materials and encourage green building techniques. And [Portland's Policy] shows how increased density can be achieved with only low-rise building, another overlooked or misunderstood reality” (Gratz, 2004). Portland's Bureau of Planning and Sustainability website provided information for comparing Olympia and Portland’s zoning regulations.
A study from 2003 published by the City of Portland Bureau of Planning, “Accessory Dwelling Unit (ADU) Monitoring Project Report 1998-1999,” was conducted to research the repeal of the ADU Owner Occupancy Requirement from 1998 (City of Portland Bureau of Planning, 2003). This project used a variety of data sources to closely monitor the ADU program. These data sources include: aerial photos, permit application, land use review applications, site visits and interviews with neighborhoods, designers and owners. The Portland Planning staff was able to monitor, track and record the decisions made based on the context of the scenario. No evidence was found for the raised public concern of an explosion of ADU development. The concern involved with tracking and recording all the ADU application cases allowed for a transparent, effective protocol.
Martin John Brown wrote a self-published article entitled, “People in Portland want and build ADU’s---with or without permits”. Brown is a resident of Portland, Oregon and an owner/builder of a permitted ADU. He was interested in studying the market value for houses with ADUs, but he quickly realized that there were very few permitted ADUs on record. In order to gain a different perspective on the market for ADUs he decided to research sales data of properties with ADU-like characteristics and find out how many possessed building permits.
With the help of a benevolent real estate agent, Brown searched the Real Estate Multiple Listing Services (RMLS) database from September 2006 to September 2009 for “single family detached” properties. Then he sifted through the property descriptions and viewed the available images to decipher if three characteristics were present: separate bath, kitchen and entrance. The properties found with these characteristics were then labeled “functional ADUs” Finally, Brown cross referenced these properties with the permitted ADUs and deciphered a ratio of permitted to non permitted dwellings from his sample population. Of the 42 “functional ADUs” discovered, 38% or 16 structures were permitted and 62% or 26 structures were not. Based on three years of real estate listings, Brown suggests the “total number of functional ADU’s in Portland could be 2 or even 3 times the number of permitted ADU’s” (2).
Brown’s study is the cornerstone research of this project. Developing a method to monitor the number of non-permitted dwelling units in comparison to the number of permitted ADUs is a way to check the efficiency of the regulation. Continuing to advance the regulation toward higher rates of compliance is the main motivation of this research.
San Francisco, California:
The Double Unit Opportunity (DUO) program of the San Francisco Development Fund from 1985-1988 provided experience that has been very influential in developing this research project. DUO offered a realistic approach to encouraging and monitoring increased density through expansion of dwelling units in unused space in single-family neighborhoods. DUO supported construction of new units and helped homeowners get building permits for illegal structures. This project worked with clients in 28 jurisdictions in the Bay Area. Their experience with navigating zoning code among 28 different jurisdictions revealed unnecessary regulatory barriers and important recommendations.
The study suggests that more illegal units will mostly likely occur where zoning standards and building regulations are the most restrictive. This report did not gather statistics on estimations of illegal units, but commonly references information about experiences with them. DUO worked with homeowners for three years to market, recruit, finance, design, build, and monitor citizens interested in building additional dwelling space in their homes. The overriding conclusion is “where ordinances are relatively flexible and the process is simple, more legal second units will be built” (San Francisco Development Fund, 1988).
Seattle, Washington:
The City of Seattle has produced a great deal of planning literature dedicated to ADUs and the new development of Backyard Cottages (BYCs). BYC is the new Seattle jargon for a detached ADU. Nathaniel Taylor Hickey’s 2010 thesis “Urban Consolidation: An Analysis of Accessory Dwelling Units and Backyard Cottages in Seattle” for the University of Washington Master of Urban Planning program offered a comprehensive overview of the history and present state of ADUs and BYCs in Seattle. Various government documents, most notably Director’s Reports from the City of Seattle Department of Planning and Community Development were also beneficial (City of Seattle, 2004, City of Seattle, 2009, City of Seattle, 2010). Seattle has had similar experiences and comparable protocol for ADUs as Olympia.
Santa Cruz, California:
The City of Santa Cruz served as a well-documented case study in the ADU research. In 2003, the City of Santa Cruz implemented an ADU Ordinance and an ADU Program. In the first year the program saw 35 new ADU permits and in 2004, 36 new ADU permits. There was over a 300% increase in permits issued after the program was implemented (Andrews, 2005). The program relied upon community outreach and advertisement in order to gain acceptance, and received a 3 year, $350,000 Sustainable Communities Grant funded by the California Pollution Control Financing Authority (Tyre, 2008). Several strategic protocol changes and incentives were implemented to make the ADU program successful.
The three strategies helped make Santa Cruz’s experience unique were: first, the city relaxed parking requirements in order to encourage ADU development. This is a monumental move in the history of ADU development, because parking requirements are almost always the notion of contention that opposition brings to the table. The second important step was a low interest ADU loan program provided by the Santa Cruz Community Credit Union and backed by the city during the years of the grant. The loans were available to homeowners who agreed to rent their ADU at low-income prices, and the stability of the loans has allowed for the credit union to offer a loan without government backing today. This technique proved to be a way a city can encourage development of low income housing with comparatively low monetary investment. Patrick Hare, an early planning advocate, published an article in 2004 identifying the “funding roulette” as the largest obstacle to establishing more ADUs. Santa Cruz’s experience has demonstrated that backing low interest loans for ADUs is a great way to institutionalize loan options for ADUs because it reduces the risk the bank assumes with a new loan program for a new housing type, and at the same time it establishes a bank protocol for ADU loans.
The final step was development of a streamlined ADU program and pre-approved architectural plan-set. The City of Santa Cruz published two books that were pivotal in the development of a streamlined ADU model. The first book is an ADU Manual that explains the step-by-step process of how to permit an ADU. This manual covers how to start, financing resources, design standards, how to be your own project manager, and appendix of helpful resources. The other book is a plan-set of 7 pre-approved architectural designs for ADUs. Citizens of Santa Cruz can choose a design from the plan-set and avoid the expense of an architect and engineer signing off. This incentive significantly reduces the cost of construction for homeowners and encourages an aesthetic that is congruent with the existing architecture. Patricia Tyre’s 2008 Masters Thesis from the University of Florida school of Urban and Regional Planning provided ample information about Santa Cruz’s methods for implementing their ADU protocol (Tyre, 2008).
Olympia: ADU History
Washington State has had a developing atmosphere for ADUs thanks to the Growth Management Act (GMA) of 1990. The GMA requires that municipalities of 20,000 and larger take action and prepare for prospected growth. The actions required by this act are to focus urban growth in urban areas. The development of High Density Corridors (HDCs) was established to locate and intensify development to reduce sprawl, provide efficient transportation, encourage affordable housing and foster sustainable economic development (Washington State Legislature, 1990). The City of Olympia adopted the present Comprehensive Plan in 1994 as part of the GMA requirements. The comprehensive plan discusses design standards, goals and policies for Olympia to shift toward more “...desirable, livable neighborhoods that provide a variety of housing opportunities, accommodate different lifestyles and income levels, and provide a sense of community” (City of Olympia, 1994). The comprehensive plan will be re-drafted in 2013 and an opportunity to continue to streamline the ADU zoning code and protocol is available.
ADUs have not taken off to the extent that GMA advocates hoped for, at least not if we look at the Olympia permitting records. Only 53 (attached and detached) ADUs have been permitted since the ordinance was passed in 1995 (City of Olympia). The zoning laws have started to accommodate for changing demands of a new demographic with the introduction of an ADU ordinance to zoning code in 1995. Based on a report prepared by the Municipal Research and Services Center of Washington, the average household size in Washington State has decreased from 3.09 in 1960 to 2.53 in 1990. The average size of families is shrinking, so who dominates the population? “American family composition has become more diverse and smaller; young singles and older persons living alone have become a dominant group” (Hickey). There is a growing proportion of people, young and old, living alone. Small habitations offer many opportunities for the growing demographic of people living alone and in smaller families.
Problems with ADUs in Literature:
According to a research report prepared by Daniel Carlson and Shishir Mathur in 2003 for the Brookings Institute, “A major stumbling block to implementing increased densities or ADU programs is parking. Standard suburban level off-street parking requirements which significantly increase development costs for multifamily housing and neighbors’ fears of loss of on-street parking to ADU residents stand in the way of these smart growth alternatives. Flexible and reduced parking standards can go a long way toward addressing these problems” (Carlson, 2003). Parking requirements are continually referenced in the literature as the largest obstacle for further density expansion in single-family neighborhoods. This is the “parking paradox,” i.e. parking requirements restrict density development, and the density is needed to sustain public transit and reduce automotive dependence. The lower densities create more dependence upon automobiles and consequently parking. Parking remains a problem that needs to be further researched and addressed, but it is not an insurmountable obstacle to increasing density and small-scale infill development.
The other concern when discussing ADUs is the social or cultural conflict. “The accessory apartment represents a deviation from the traditional image of housing, family, and neighborhood. It symbolizes a change in the way the single family house is used, a change that clashes with the traditional meanings attached to the categories of residential zoning” (Gellen, 1985). The population demographics research reveals that ADUs are needed for the change in population dynamics in the near future, so why would the cultural identity of America resist ADU development? Home-ownership has stimulated American economy. The “American Dream” of a single family detached house (de Neufville and Barton, 1987) acts as a dominant cultural driver.
In Constance Perin’s classic work, “Everything in it’s place: Social Order and Land Use in America,” she dissects the foundation of zoning laws through observation of cultural patterns. The goal of a home and family is glorified as the top rung on the symbolic ladder of achievement (Perin, 1977). The cultural identity of America will not waver with the advent of further utilization of the single-family residential neighborhoods. “The American system of zoning is based on an implicit value judgment about the ordering of land development where single-family neighborhoods reign over apartments and all other housing types” (Hickey, 2010). The acceptance of ADU ordinances across the country shows incremental steps toward public acceptance of a new housing option. The worries of ADU opponents will be softed with the documentation of increased property values instead of the preconceived fear of neighborhood blight.
While the ADU can be perceived as a direct assault on the single-family neighborhood, the ADU represents a symbiotic relationship with single-family housing to create new dwelling options. Increasing density is a set goal for the City of Olympia and while the ADU does represent a change in the classic image of a single-family neighborhood, it works in conjunction with the existing infrastructure to diversify options.
How is this Research Contributing to the Literature?
According to a comprehensive literature review published by the UC Berkeley Institute of Urban and Regional Development, by Jake Wegmann and Alison Nemirow, ADUs and permitted Accessory Structure dwellings are being recognized in the literature as “new” forms of suburban/urban infill development (Wegman, 2011). Infill development is usually associated with purchasing larger tracts of land and re-developing all of it to take advantage of economies of scale. It is expensive to buy land within a city, demolish it, perform environmental analysis, remediate and build again. Piecemeal infill development in the form of attached and detached dwelling units utilizes private investment to fund this form of micro infill development (Wegman, 2011). ADUs do not expand the footprint of the built environment, but concentrate use. The concentration of use may well increase the impervious surfaces and use of land within city limits, which will have environmental effects. However, increasing density remains a goal for Olympia, for a variety of reasons, and this style of housing has a low impact comparatively with other forms of development.
“Urban infill has steadily increased in prominence in recent decades as an area for research and praxis, but those studying this topic have had little or nothing to say about its manifestation at the smallest spatial scale, and with possibly the potential for greatest ubiquity, namely the secondary unit.” (Wegman, 2011). This literature review revealed a lack of proper monitoring of secondary dwellings and the common problem of non-permitted dwelling units. There was little research on non-permitted structure estimation and the research found was mostly focused in major metropolitan areas, New York and San Francisco (San Francisco Development Fund, Chhaya Community Development Corporation). No scholarly assessment of Accessory Structure dwellings was identified in the literature and the phenomenon of Accessory Structure dwellings remains poorly research and documented.
Now to discuss the research methodology. In light of the lack of monitoring of ADUs, Martin John Brown’s model is replicated to characterize the ratio of permitted and non-permitted ADUs in Olympia, Washington.
