high rents
affordable housing
aging in place
neighborhood character
sustainable development
local investment


… as Portland continues to grow, we all struggle with development pressures that impact the fabric and character of our community. We believe that ADU’s offer powerful solutions to these challenges, especially in some of our denser residential neighborhoods. A well-designed ADU provides opportunities for aging in place, creates affordable housing opportunities, and promotes greater diversity and more housing choices. Some homeowners choose to downsize their lifestlye and move into their ADU while renting their home, using the rental income to allow them to keep a property that might otherwise be hard to afford.


In many neighborhoods, insensitive redevelopment is having an adverse impact on the quality of the streetscape. Developers tear down a perfectly good old home to build something larger, or partition the lot to add density. ADU’s are a better way to add that density, preserve the primary home along the street, and avoid sending a perfectly good house to the landfill. An ADU can be an excellent way to add square footage to your home while you need it (for kids, or a home business), and convert it to a rental or in-law unit as your family’s needs change. For all these reasons, an ADU can be a good strategy to extend the life of your home and your time in it. As a landlord, building an ADU on your rental property is a very profitable way to expand your portfolio without a significant increase in overhead, tax exposure, or service utility costs.


Nicholas Papaefthimiou | AIA, LEED BD+C


infillPDX was founded by Nicholas Papaefthimiou who continues to lead the design and development efforts. Nicholas is a licensed architect and contractor with nearly 20 years’ professional experience across the Unites States and Europe. He holds Masters Degrees in both Architecture and Structural Engineering from the University of California, Berkeley and Bachelor of Science degrees in both Architecture and Urban Planning from the Massachusetts Institute of Technology.  In 2014, he founded infillPDX, a design and research collaborative focused on the development of financially, socially, and environmentally sustainable models of infill housing models to address Portland’s housing crisis.


Nicholas brings the same care and rigor to all of his work, which ranges in scale from award-winning religious and residential architecture to his role as Lead Project Architect for the largest design/build contract in the United States.  He has served on multiple design and awards juries, organized and presented at numerous symposia, and served on several graduate school admission boards.  He currently teaches at the University of Oregon and lives in SE Portland with his wife and two daughters.