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“We built both dwellings new. The estimated total cost is a guess at the marginal cost for adding the ADU because some of the structure – roof, foundation and utilities – are already accounted for in the main dwelling unit’s costs.” – Robert Albano
Accessory Dwelling Units – or Secondary Dwelling Units as they are known in Eugene, OR – were first added to the Eugene land use code around 2003. In 2011 Robert & Kathleen were living in an established 2-block neighborhood which had just hosted its 22nd annual 4th of July party. Kathleen and Robert appreciated that their neighborhood was very social in comparison to others. So they decided to create long-term housing options for themselves in this neighborhood by building a new house with an ADU. Kathleen and Robert felt that the ADU would provide additional income and increase the chance for casual social interaction with their neighbors. The lot that the ADU and main dwelling unit were built on was one of the few remaining empty lots in the neighborhood. They financed the project with savings.
Robert explains that at the time, the SDU regulation read: “The dwelling shall not exceed 800 square feet unless occupying the full story of a multi-story structure with ground floor residential use.” In order to get a slightly larger SDU Robert and Kathleen decided to dedicate the entire ground level to the SDU with the primary dwelling above it.
Since the alley at the back of the lot is about 15’ lower than the street Robert was able to place the main dwelling unit at street level and the ADU slightly above alley level. This resulted in the ADU being wheelchair accessible from the alley via car. The main dwelling is wheelchair accessible from the street. Both units also have 36” door framing and wheelchair accessible bathrooms.
Accessibility, sociability, rentability, and sustainability were driving factors for their design. The focus of the design was aging-in-place for both dwellings. A secondary goal was energy-efficiency so that the dwellings would be less expensive to heat and cool. They insulated the units with R-40 walls and an R-60 roof. Tight air sealing was also important and they ultimately achieved 2.2 Air Changes per Hour (ACH).
“Energy-efficiency is especially important as energy costs are expected to rise in the future where as retirement income may not keep pace. Also low energy costs make the ADU a more competitive rental.” – Robert Albano
Robert and Kathleen designed both units to be accessible so that they would have flexible housing options over time. They could live in either unit and rent out the other.
“The 3 bedroom ADU size allows for a more flexible use. Parents and two children can each have their own bedroom. This is in fact our first tenant: two university professors and their two children. We go to each others parties and see each other on the way to our front doors.” – Robert Albano
Robert explains that the ADU began increasing neighborhood interactions even before it was complete. He says that as it was being built people walked by and asked questions about it. During construction many people who were already living in the area came by and one of them ended up renting the ADU when it was finished.
“My favorite thing about the ADU is how it has increased social interaction with the neighborhood kids. Because it is on the hill slope, there is an area next to ADU that is under the primary dwelling and is sheltered from rain. The kids in the ADU as well as neighborhood kids use this as a place to play during the rain in winter and place to escape the heat in the summer. It has built-in lighting and I have provided a workbench and scrap wood from construction for the kids to play with.” –Robert Albano
If he had it to do over again, Robert would have designed the units to meet passive house standards. The biggest change would be to use windows certified to meet passive house standards which would have made the house more air-tight. He also would have provided more external long-term storage for the tenants. He explains there is adequate internal storage but not enough for seasonal items like Halloween and Yule decor that usually would be stored in garage. He notes that some of the area under the house may be converted for that use.
So what advice does Robert have for homeowners considering creating an ADU on their own property?
“Design for a variety of users: families, students, and adults sharing a living space and make it accessible and energy-efficient.” –Robert Albano