Completed in 2023 the 13th Avenue Apartments features one of b9 architects’ cleanest and simplest designs to date. Seeking our help in 2018, the client had already gone through an early design process with another architect, but the design they arrived at could not be realized due to code compliance issues. Through a flexible and collaborative design process, the team created an elegant, 20-unit infill project, mid-block on 13th Avenue in Seattle’s Capitol Hill neighborhood. With an elegant and organized facade that belies its complicated design, the 13th Avenue Apartment represents excellence that can be achieved with the right client, material selection and detailing.

When the project first came to b9 architects, it looked very different. With another firm’s preliminary Design Review proposal that did not have a path to meeting Seattle’s land use, energy or building codes, our design team worked with the client to propose a new solution. After an initial site investigation, the client agreed to have b9 restart the design process, keeping the idea of two structures, but connecting them with a series of stacked exterior walkways and interior stairwell and elevator. This strategy allowed the “front” structure to act as a centerpiece for the design while the structure in the rear could act as a secondary element. With an engaged client and multiple b9 team members owning specific aspects of the project, the design process focused on collaboration and quick decision making to move the project forward, helping the client make up for lost time.

The project design takes advantage of the “single exit” allowance in the Seattle Building Code. Limited to 4 units per floor and a maximum distance between each unit’s entry and the stair and elevator, the project benefits from providing only one stair. The elevator permits the project to provide a small roof deck for all residents with access to amazing views of downtown Seattle, the Puget Sound and the Olympic Peninsula and Olympic Mountains beyond. The circulation spaces are the “connector” described above that tie the front and rear portions of the structure together. From the street, the building reads as two elements due to the circulation being inset from the north and south side facades. The rear facade shifts half of the mass to provide relief for the homes across the alley and to create a variety of unit types within the project.

Due to the dimensions of the site, the modulation at the center of the site creates relief to adjacent sites, similar to many of b9’s infill housing projects.  However, the difference at this site is that the front facade is purposely clear and simple. The Design Review process in Seattle frequently encourages projects to undulate massing to create depth along street frontages. With a site at 35’ wide by 120’ feet deep, we were adamant that the front façade should be flat and create depth and texture primarily with material expression. There is no space for the front facade. Instead of shifting in or out, the 13th Avenue Apartments relies on simple detailing, a brick frame or grid complemented with contrasting infill panels and large windows and doors. As an assembled integral colored material, brick creates texture and depth on the front volume of the project. Limited to two projecting balconies, this is the simplest front facade b9 has designed. When taken as a whole, the project is complex, carving out the center of the site to setback from an adjacent Single Family home to the south and established brick apartment to the north.

As part of its plan to increase housing options in the city and to find solutions to solve missing middle housing, the City of Seattle has recently changed regulations around accessory dwelling units. Commonly referred to as a mother-in-law apartment,  an accessory dwelling unit is a smaller residential unit tied to a single family house that comes in both an attached and detached typology, known as ADU and DADU respectively. Picture a finished basement with its own kitchen and entry from the rear or a separate cottage on the same property.

In previous years, the Seattle Municipal Code enforced by the Seattle Department of Construction & Inspections (SDCI), required two significant items that dramatically reduced the feasibility of ADU or DADU projects. One, each ADU required onsite parking be provided, and two, the property owner would have been required to physically reside in one of the units on the site for at least 6 months out of the year.  In addition the units were limited to 800 square feet. The former requirement ate up valuable footprint space making a lot of Seattle sites, especially those with environmentally critical areas like slopes and wetlands, too small to add an additional structure, and the latter often priced out any developer beyond a homeowner interested in taking on construction risk to invest in their property. In 2019, the City of Seattle removed these requirements and began allowing two ADU’s per lot. Since then Seattle has seen an increase in this type of project entering the permitting process.

While this change definitely encouraged the development market to explore another avenue to create housing, the ADU/DADU cluster has very little difference to a project type we at b9 architects are already familiar with; namely, the duplex and Single Family house, or even a three unit townhouse development. Where the two differ most is in zoning and size.

As a part of the change to the municipal code that allowed this type of project to flourish, the City has made this three unit typology admissible in all Neighborhood Residential zones (formerly Single family residential), a zone that until this change could only allow one house with one accessory dwelling unit. With this change, a significant portion of land in the City of Seattle has been unlocked as developable. The trade off is in size. While Seattle’s multi-family zones would allow three townhouses of any size (so long as they meet FAR guidelines) this typology limits an ADU or DADU to no more than 1,000 sq ft each, with allowances for storage and garages that exceed that amount. 

The 335 DADU is a small backyard residential unit completed in 2017. This would have been the only typology allowed in Single Family zones.

The 335 DADU is a small backyard residential unit completed in 2017. This would have been the only typology allowed in Single Family zones.

If you look at our 2018 study Urban +, you’ll see how the backyard building can range in size and scale based on the lot number, size and zone. In 2018, the only thing that could be done with a single lot in the Single Family zone is what you can see in our 335 DADU project. Since the code changes, the new type of project could resemble the configuration of several of our completed projects, including Urban +, Urban Share, or the North lot in Row 1412. In 2022 we used our expertise in Urban + to help two of our clients approach this type of project.

An axon of the 335 DADU. This project could add an additional ADU based on new requirements.

An axon of the Judkin’s Park House. This configuration would not be allowed in Neighborhood Residential zoning due to the location and size of the two homes.

An axon of the Urban Share project. While it’s three units, this configuration would not be allowed in Neighborhood Residential zoning due to the location and size of the two homes.

The Genesee ADU Cluster in West Seattle will add five residential units across two sites of current single family homes. One of these primary residences will be retained and converted to the allowable DADU for that lot. The other existing residence will be removed to make room for the new dwellings. The duplexes (or Single Family w/ ADU) that face the two streets are three stories with living on the second floor. Each new unit has at least two bedrooms, with the two larger units designated as Single Family Houses having three bedrooms. Similarly, in our project Urban Share, a Single Family home remained on site while a duplex was built behind it. If Urban Share were on a Neighborhood Residential zoned lot today, the two small units in the duplex would be comparable in size to what is allowed now as an ADU or DADU.

The Genesee ADU Cluster retained an existing Single Family House.

Due to being a corner site with access to two streets, we are position the existing Single Family house behind a new structure, and designate it as the site’s DADU.

The site plan for the Maple Leaf ADU Cluster is organized to give each of the three units a private outdoor space. While each of these spaces is accessible to all three units, they are recessed from the street and are configured like a checkerboard with each unit exiting through a rear door onto an established space. Due to the new code allowances, parking is only provided for the front Single Family home in a ground floor garage.

In the end, the driving factor for the large increase in ADU and DADU development in Seattle is cost, specifically related to the process required to obtain a permit for construction. These three unit projects, while being similar to a three unit townhouse project, are not required to participate in the city’s Design Review program, or comply with the requirements of the Mandatory Housing Affordability program. This streamlines the entitlement process, and saves money while being more predictable. While this will help bring the much needed residential units to the area, it will increase the amount of small ADU and DADU units that come to the city, which offers a more affordable option in the market.

Happy New Year! At b9 architects, we have the good fortune of having a large portfolio of completed works. Due to the diligence and expertise of our clients, the majority of the residential projects we’ve designed are completed, a feat not all architecture firms have. In 2022, we examined a couple projects that, due to the economic realities of Seattle, were canceled mid-process. Due to the increasing costs of construction, longer permit entitlement processes, and current incentivisation programs in the municipal code - creating dense, rentable residential units is not always cost effective, especially on small or complicated sites. Here are case studies of two projects that did not move forward.

Midvale Apartment

The Midvale Apartment Building and its surrounding neighborhood were up zoned when the City of Seattle implemented the Mandatory Housing Affordability (MHA) legislation in 2019. Properties facing the main arterial, Stone Way, remained in the Neighborhood Commercial zone but received a height and allowable area increase.  The neighborhood to the west was largely shifted from the exclusive Single Family zone to the more flexible Residential Small Lot zone. Our site, however, and everything on the half block between the two received the intermediate Lowrise Multi-Family designation. 

As a potential transitional space between the more active Commercial Stone Way and the classic Seattle Single Family neighborhood, this site appeared to us as a space designated for small-scale, dense, rental housing. But in implementation, the zoning allowance does not reflect the true cost. A family-sized unit requirement, a one-time MHA fee payment, and construction complications made an apartment building at this site with the height and area restrictions infeasible. 

This Axonometric View of the surrounding blocks of the proposed project on Midvale Avenue North represents the existing zoning and development and in particular, it diagrams the different scales of surrounding residences and buildings between zones

While the MHA implementation unlocked this half block strip for potential multifamily redevelopment, higher density housing came with a family-sized unit requirement. For every 4 proposed units, one 2-bedroom (minimum 850 square feet) or for every two 2-bedroom units a single 3-bedroom unit (minimum 1,050 square feet) must be provided. In addition, any development under MHA (that does not provide affordable housing on site as part of the development) incurs a fee that must be paid to the city of Seattle before a building permit can be issued. The fee is a variable dollar amount per square foot that changes based on location within the City and the extent of the upzone. Alternatively, a project can choose to designate a portion of their units to rent for significantly less than market value for the first 75 years of the project. In our experience, the client almost always chooses the fee due to the complication of renting units through a city managed program and the future potential loss of rental income. At the same time, construction costs due to a lack of staging space on midblock sites, supply chain issues, and other national economic difficulties caused our client to rethink this project and focus elsewhere. The multiple requirements that previously would have made the projected income tight, but feasible, became too constricting as the project became short on projected rental income and desired number of overall units. We believe the zoning intended to create small apartment buildings with family-sized units, providing increased density near a commercial zone while also transitioning towards the more residential blocks of the existing neighborhood. Instead, due to the complexity described above, small townhouse structures and additional single family dwellings are being developed along this same zoning block. This is achieving a greater density than what previously existed, but still is creating single-family living at higher cost to future residents. Following the permitting of the small-scale 13-unit apartment building, our client chose to sell the site, resulting in the creation of a single family unit and a duplex structure.

As much as the City of Seattle needs to solve the lack of affordable housing and needs the addition of more family-sized rental units to the housing market, passing the cost of multiple housing initiatives - when applied at such small infill sites - onto the developer incentivizes the developer to avoid them entirely, where they instead pursue more predictable  projects with a greater financial upside and less risk.

Pictured is the proposed apartment project viewed from Midvale Ave N to the Northeast

An entry sequence was designed to bring residents and guest to the central open space of the site

The central space was designed to feel very open to allow air and light to activate the site and shared apartment spaces and to provide neighboring sites with massing relief

Fir Street

A very small site in Seattle’s Midrise Residential zone, the Fir Street project came to b9 architects as an apartment, proposed to take advantage of the increased capacity allowed under the MHA upzone. 

The site is located on a small peninsula of Midrise zone that is adjacent to the Yesler Terrace Master Planned Community and to the south of a small Neighborhood Commercial zone.  This site is visible from adjacent rights-of-way as it is surrounded by two parking lots and a garden owned by the neighboring Japanese Baptist Church to the west and the north, with an alley to the east. A pocket park is located across the street and the immediate context features many large new multifamily apartment structures that are part of the Yesler Terrace Master Planned Community.  

This Axonometric View of the surrounding blocks of the proposed project on E Fir Street and Broadway depicts the existing zoning and development and in particular, it diagrams the much larger scales of surrounding residences and buildings as well as the relative small size of the lot occupied by the proposed project.

The originally proposed massing for apartments on E Fir Street

The site dimensions and height allowance result in a vertical structure that helps anchor the pocket park across E Fir Street to the south and respond to the larger surrounding developments.  The proposal addresses this unique circumstance and emerges from a clear design concept. In response, the massing consists of an aggregation of “basalt columns” of various widths and heights.  These columns combine to create a subtle, yet dynamic building mass and landscape concept.  This design concept produces numerous modulations and material changes along all facades of the building.  The termination of the “columns” at different elevations along the facade creates opportunities for balconies, which further activate the facades of the building.

The project’s height is consistent with many of the newer buildings in the Yesler Terrace Master Planned Community to the south and west while the footprint is more consistent with the fourplexes, townhouses, and smaller apartment buildings to the east and north. Due to the small lot area, 2,400 square feet, the building would be unlike anything in the neighborhood. An innovative, 6-story apartment building, this Yesler Terrace project, touted by the DJC as an “infill infill project” would have yielded 15 rental units. The project was required to go through the city of Seattle’s Streamlined Design Review process as part of the permitting process.  Through this process, we proposed modifications to reduce the setbacks required in Seattle’s land use code in order to achieve the project goals of an infill apartment on this incredibly unique site. In our experience Design Review can and should allow for flexibility in order to respond to unique sites such as this one.  The design proposal was significantly less area than what is allowed by code. Unfortunately, the Design Review process resulted in a strict application of the land use code, eliminating the necessary area to make the “infill” infill apartment feasible. That, combined with the cost of construction, became untenable and so the project shifted to a less risky townhouse scope.

The proposed massing for the project featuring 15 units provided on site

The current proposal for 3 townhomes on the same site, currently in process

The height and capacity allowance in the Midrise zone, does not have the incentives necessary to take full advantage when the site does not conform to certain characteristics including size, access to utilities such as storm and sewer, and being clear of environmental critical areas like steep slopes or wetlands. While b9 architects, inc. enjoys designing townhouses and seeing their impact on the City, we recognize a need for a variety of housing solutions.

Over the past 20 years, b9 architects has garnered expertise in maximizing Seattle’s sites in smart and well-designed ways. Clients often choose our firm to help them navigate difficult sites, or design innovative projects to compete with larger rental properties down the street. In our experience, these small 10-30 unit infill apartments tend to be the projects most difficult to meet the financial model necessary to build. If the market isn’t completely on board, developers stop completely or change typology.

In 2023, we hope to explore ways to incentivize small and medium multifamily solutions to help our clients and partners better achieve the combined goals of better, denser, and more affordable housing in Seattle’s neighborhoods.  This will include examining the necessary code changes to expand the access to housing opportunities and levels of affordability in the current Neighborhood Residential zones.