ACCESSORY DWELLING UNITS (ADUs) & STUDIOS

Accessory Dwelling Units (ADUs) are also known as Mother In-law units, guest houses or by many other names. The key is that they are an additional, fully functioning dwelling unit on a residential property that includes a full kitchen, bathroom and separate address. Some of the many ways ADUs are utilized are as follows :

- Add space that can act as guest quarters, studio space, or as a rental. 

- Create additional rental income on an existing rental property.

- Provide a new residence for the owner to live in so that the main house can be rented.

- Create space for parents or adult children for a multi-generational living arrangement.

ADUs can be a separate building (detached) or they can be a part of the main house (attached) either as a self sufficient addition or by subdividing part of the existing house to create an ADU (often an attic space or basement, for example). Existing garages can also often be converted into ADUs. See our guide to ADU resources.

We also design small accessory structures which don't qualify as ADUs. These can be art studios, guest houses or flex spaces.

Below are some of the ADUs and studios designed by Polyphon :


RELATED BUILDING TYPES WHICH YOU MAY ALSO FIND INTERESTING :
RESIDENTIAL


LIBERTY ST ADU - GARAGE CONVERSION

 

LOCATION:  CONCORDIA NEIGHBORHOOD | PORTLAND, OR

SIZE: 355 SQ' (245 SQ' GROUND FLOOR + 110 SQ' LOFT)

STATUS: COMPLETED 2015

CONTRACTOR: ENVIRONS LLC

This project aimed to transform a dark attached garage into a light-filled, fully functional, ADU. There were many constraints on this project the greatest of which was the  extremely limited size. Through a focus on natural and exposed structural materials, the design strove to make use of all possibly available space. The stair had to be a very transparent element in order to maximize southern light in the lower floor. 


OVERLOOK ADU

LOCATION: N | PORTLAND, OR

SIZE: 800 SQ' ADU + 500 SQ' GARAGE

STATUS: PERMITTED

CONTRACTOR: OWEN GABBERT LLC

This new ADU replaces an existing storage garage and serves a number of functions. It provides a usable garage with large bike storage area and it creates a 2 bedroom 1.5 bath ADU with a roof deck which faces south and provides a private patio which completes an upstairs master suite. The ADU has a modern design language but works within the new guidelines for ADUs which do not match the existing house. The ADU focuses on both the connection of indoor/outdoor space as well as natural light. 

 

 


WOODWARD ADU

LOCATION: SE | PORTLAND, OR

SIZE: 440 SQ'

STATUS: DESIGN

CONTRACTOR: HAMMER & HAND

 

This project involved a number of renovations to the existing house on the property but the keystone of the project was a new ADU. The ADU worked within the new City of Portland code which allows for ADUs and other accessory structures to sit within the required building setbacks. The design prioritized flexibility of the space for future uses and a palette of natural materials including ground faced CMU, a green roof, exposed wood beams and stained wood siding. 


GLADSTONE STUDIO/WOODSHOP

LOCATION: SE | PORTLAND, OR

SIZE: 700 SQ'

STATUS: COMPLETED - 2015

CONTRACTOR: ENVIRONS LLC

 

This new building houses a wood shop/garage at ground level and a studio and roof deck above. The building has been split into two forms to decrease the size of the building mass and also to create additional outdoor spaces above and below the forms. The owners wanted a two story space in order to preserve limited backyard area but did not want an imposing two story structure that would dominate the rest of the yard space. The new structure and outdoor areas had to be tightly interwoven with the existing deck and yard to maximize the usefulness of the limited space.


RODNEY STUDIO/GUEST HOUSE

LOCATION: NE | PORTLAND, OR

SIZE: 230 sq'

STATUS: COMPLETED - SUMMER 2014

CONTRACTOR: JRA GREEN BUILDING

This quaint, backyard, detached addition will serve as a music studio, art space and guest sleeping quarters while preserving as much of the existing backyard and gardens as possible. It has a compact but full bathroom, making this a highly flexible and functional addition to this cozy, NE Portland home. 


PRESCOTT ADU

 

LOCATION:  KING NEIGHBORHOOD | PORTLAND, OR

SIZE: 750 SQ' ADU + 150 SQ' BIKE GARAGE   

STATUS: COMPLETED - 2013

CONTRACTOR: JACOB LEE AVERY

The client for this project wanted to build a space for himself behind an existing rental house that he owns. The ADU consists of a bedroom, bathroom, and office lofted over a open kitchen and living space. There is also a large bike storage and repair area attached.  The design focuses on openness, ample day light and exposing structural materials such as the polished concrete slab and exposed wood beams and decking of the loft which doubles as the ceiling over the kitchen.


CONCORDIA ADU

 

LOCATION: CONCORDIA NEIGHBORHOOD | PORTLAND, OR

SIZE: 470 sq' (320 sq' + 150 sq' loft)

STATUS: COMPLETED

CONTRACTOR: GREEN HAMMER

The Concordia ADU is a 1 bedroom, 1 bath ADU built on a small footprint. It has an open plan ground floor with double height ceilings that open to the stairs and loft bedroom. The project is small but went to two stories in order to maximize yard area and capture views of Mt. St. Helens. A key to this project was proper siting to allow the project the possibility of being rented out without sacrificing the privacy of the main house. 


KILLINGSWORTH GARAGE CONVERSION ADU

LOCATION: NE | PORTLAND, OR

SIZE: 624 SQ'

STATUS: COMPLETED - 2016

CONTRACTOR: ENVIRONS LLC

 

The client for this project came to us wanting to turn a dilapidated garage into an ADU to use as their primary residence and rent out the main house on the property. Polyphon was tasked with refurbishing the existing CMU structure and coming up with a layout which maximized natural light despite two of the building walls being prohibited from having windows due to code issues. The finished project features a stained concrete floor, reclaimed wood trim salvaged from the remodel and original finishes throughout.


AINSWORTH ADU

 

LOCATION: WOODLAWN NEIGHBORHOOD | PORTLAND, OR

SIZE: 770 SQ' 

STATUS: UNDER CONSTRUCTION

CONTRACTOR: GREEN HAMMER

This ADU will supplement an existing rental property and replaces an existing, underused, single-car garage. Roughly occupying the same location and footprint as the old garage, the new ADU will be a two-bedroom, one-bath home with covered parking. Above the covered parking space  is  an elevated deck to provide outdoor space for the tenants that is separate from the existing yard. The design makes use of abundant southern solar exposure and is heated by a ductless heat pump system.  

This project is featured on the 2nd Annual Portland ADU tour on the 30th of May, 2015. Find out more information over at AccessoryDwellings.org


ARBOR LODGE ADU

LOCATION: N | PORTLAND, OR

SIZE: 650 SQ'

STATUS: DESIGN

CONTRACTOR: DAVE RUSH

 

A new ADU with a small footprint.


LOCATION: ALBERTA ARTS | PORTLAND, OR

SIZE: 800 SQ' ADU  

STATUS: DESIGN

CONTRACTOR: TBD

A new 2 bedroom 1 bath ADU in the Alberta Arts District. 


CONTAINER ADU

 

LOCATION:  PARKROSE NEIGHBORHOOD | PORTLAND, OR

SIZE: 700 SQ' ADU + 200 SQ' OUTDOOR AREA  

STATUS: DESIGN

CONTRACTOR: TBD

There are many challenges to with using shipping containers for residential uses. This design tries to maximize the inherent strengths of the containers while creating open and flexible spaces. The project also aims to highlight the reuse of the containers while providing a tight and efficient building envelope. The project is a two bedroom, 1 bathroom configuration with the option of opening the second bedroom to the living space to provide more openness.   


SUMNER ADU + STUDIO

 

LOCATION:  ALBERTA ARTS NEIGHBORHOOD | PORTLAND, OR

SIZE: 650 SQ' ADU + 200 SQ' STUDIO   

STATUS: DESIGN

CONTRACTOR: TBD

This project lies very close to bustling Alberta St in NE Portland and aims to strike a delicate balance between creative density and privacy.


ALLEYWAY ADU

 

LOCATION: PIEDMONT NEIGHBORHOOD | PORTLAND, OR

SIZE: 800 sq' (+150 sq' bike storage) 

STATUS: UNDER CONSTRUCTION

CONTRACTOR: ENVIRONS LLC

This project is a proposed new ADU with separate bike storage, located in the Piedmont Conservation District of N/NE Portland. Project goals include minimizing the building footprint to conserve yard area, engaging the paved alleyway at the back of the lot while maintaining privacy, and orienting the project to maximize sun exposure while respecting the privacy of the main house and yard. The bike storage is located in a separate building with a planted roof. A covered entry-way connecting the ADU to the bike storage acts as an intermediate zone between the yard and the alley and doubles as a deck off of the 2nd floor bedroom. The ADU will have two bedrooms, one bathroom and an open floor plan kitchen and living area which opens up to the yard.


APPLEWOOD CORNER ADU

 

LOCATION: SOUTH TABOR | PORTLAND, OR

SIZE: 780 sq'

STATUS: COMPLETED

CONTRACTOR: ORANGE SPLOT

This ADU was developed under a different model than typical ADUs. The owner is local sustainable developer Eli Spevak of Orange Splott LLC. The ADU and existing house were created as condos and sold separately as a way to provide, increasingly rare, small scale housing stock as well as a micro community within the neighborhood. With many nods to the existing house, the ADU has a strong street presence and is oriented for light and orientation to communal gardens and gathering areas. 

 

You can read more about this project:

Oregonian Article from 11/25/2016

Developer (Orange Splot) Project Description


LITTLE HOUSE

LOCATION: NE | PORTLAND, OR

SIZE: 200 SQ'

STATUS: COMPLETED SPRING 2010 

This little house was designed as a mother-in-law unit for a real live mother-in-law. Compact and efficient spaces paired with rich, reclaimed materials lend this small space expansiveness but also privacy. 

You can read a more in depth account of this project on AccessoryDwellings.org


ALBERTA ADU

 

LOCATION: CULLY NEIGHBORHOOD | PORTLAND, OR

SIZE: 650 SQ' 

STATUS: UNDER CONSTRUCTION

CONTRACTOR: DESIGN BUILD PORTLAND

This ADU project is to be the new home for a family member of the main house. This design boasts a highly efficient layout, with an open kitchen & living room, bathroom and office on the first floor; and second floor bedroom which is open to the lofted living space below. Large windows on the southern facade provide abundant natural daylight into the lofted living space. Patio doors off of the main living space open to the backyard, extending the living room into the outdoors. A side porch provides shelter over the main entrance and acts as a buffer between the new ADU and the existing house.


WYGANT ADU

 

LOCATION: OVERLOOK NEIGHBORHOOD | PORTLAND, OR

SIZE: 710 SQ' 

STATUS: COMPLETED 2014

CONTRACTOR: ENVIRONS LLC

The Wygant ADU is a one-bedroom, one-bath dwelling with open living area and a generous open loft. The main goal of the project was to create a visual extension of the existing house and provide separate living quarter's for the mother of one of the clients.

 

 


GOING ST. ADU

 

LOCATION: CONCORDIA NEIGHBORHOOD | PORTLAND, OR

SIZE: 576 SQ' 

STATUS: COMPLETED 2013

CONTRACTOR: DESIGN BUILD PORTLAND

This garage to ADU conversion is being completed to Energy Star NW standards, turning an under-utilized garage into a two-bedroom, light-filled space that is activating one of the many unfrequented alley's of NE Portland. Radiant floor heating, sliding translucent glass doors and a full energy retrofit are part of this conversion.