4017 NE Rodney

Building Data:
Neighborhood: Boise
Year Built: 1911
Typology: Duplex-Stacked
Units: 2
Stories: 2
Site Area: 5,000sf
Building Area: 2,472sf
FAR: 0.5:1
Density: 17.5 du/net acre
Zoning: 1 (1du/5000sf of site area)
Is it Legal? YES

4017-4018 NE Rodney is an excellent example of the classic stacked duplex typology. While this one appears to have been constructed as a duplex, many of Portland’s stacked duplexes were the result of conversions. Many of these conversions occurred during WWII when the city was experiencing a severe housing shortage due to the influx of war industry workers. Note that unlike today, the newcomers were, by and large, blue collar workers.

This type of duplex has trade offs. The ground floor unit has more access to the yard than the top unit, but in many cases, a usable attic is available to the second floor. Sound transmission through the floor can be an issue. On the upside, the floor plans are pleasant and efficient, with much less space wasted on redundant circulation. We’d wager these units’ interiors are pretty similar to single story bungalows of the same era. Additionally, the shared yard and shared entry facilitate community.

Contemporary side-by-side duplex.

Very few of these seem to get built today. In fact, we have located only one contemporary stacked duplex thus far. Developers seem to favor side-by-side duplexes. These can be sold as single family attached houses, which are an easier deal for small unsophisticated builders who do not want to build and hold. They are also easier to park.  

Site Plan

 

2022 NE 8th

Building Data:
Neighborhood: Irvington
Year Built: 1949
Typology: Duplex/Cryptoplex
Units: 2
Stories: 1
Site Area: 5,000sf
Building Area: 2,476sf
FAR: 0.5:1
Density: 17.5 du/net acre
Zoning: 1 (1du/5000sf of site area)
Is it Legal? YES

Introducing the cryptoplex! As the name implies, this is a stealth duplex. Viewed head-on, this appears to be a very ordinary cottage-vernacular single family home. Step to the side, and you’ll see a second front door, perpendicular to the one seen from the front. The two entries share a common approach and front porch. On paper, this duplex is pretty indistinguishable from the twin house we profiled a couple weeks ago. Its stealthy nature is a unique design feature, and we feel it warrants its own sub-species classification in our housing taxonomy as a result. We’ve located three of these so far, but we suspect there are many more, hiding in plain sight.

Oblique view showing door placement.

There are other approaches to the cryptoplex, which we’ll explore later, but note for now, that this one, by virtue of main entry location, maximizes interaction between tenants and fosters community.

Cryptoplex Layouts. Case study house left. Portland development code standard with separated entries right.

The Portland development code has encouraged duplexes in corner lots in all residential zones for some time now. However, the code standards require entries on perpendicular faces. On the positive side, this policy activates both facades, and ensures that buildings don’t turn their backs on one of the street frontages. The downside is that it misses an opportunity to create community. On mid-block sites, the latter seems like a win-win. As more of the city gets upzoned to multifamily, this approach is worth exploring and potentially codifying in our zoning code.

 

The Louie

312 NE Monroe

Building Data:
Neighborhood: Eliot
Year Built: 2014
Typology: Small Apartment building / Walk-up with townhouse units
Units: 12
Stories: 3
Site Area: 5,000sf
Building Area: 8,000sf
FAR: 1.6:1
Density: 104.5 du/net acre
Zoning: RH (no maximum density)
Is it Legal? YES

The Louie is a particularly fascinating case study of a small apartment building. There’s a lot to like here. This is a small apartment building built just four years ago, located about 100’ off MLK Blvd. north of the Lloyd District. Let’s set aside, for now, the somewhat clumsy architectural expression on the front façade – sprinkler controls and fire alarm occupying the most prominent place on the façade? Was there really nowhere else to place this stuff?

But moving along, this resembles a well established historical apartment building type, and one that most people are pretty comfortable with. Like its historical precedents, the Louie is a three story building on a single 5000sf lot. This is the same size as a standard single-family house lot. This format was quite common 100 years ago and many were built in close in neighborhoods.

1920s small apartment building on a single lot.

Unlike the typical 1920s buildings, which had 2-4 identical floors consisting of a central corridor and units on either side, the Louie has units that run all the way from one side of the building to the other, allowing two window-walls in all units (three on the ends).

Site plan: the notches represent stairways to the upper units.

The ground floor units enter from doors on the east wall, while the upper floors are actually townhouses. One walks up a flight of steps to enter the units lower level. Once inside, a stair leads up to the bedrooms on top.

This creates some real diversity of housing types in a single building and in the market at large as townhouse units are exceedingly rare in the US.

Now if they could just do something about those mechanical gubbins where the front door should be…

 

2234-2240 NE Everett

Building Data:
Neighborhood: Kerns
Year Built: 1924
Typology: Duplex / Twin House
Units: 2
Stories: 1.5
Site Area: 3,184sf  
Building Area: 2,268sf
FAR: 0.7:1
Density: 27.3du/net acre
Zoning: R2.5
Is it Legal? No

This house in the Kerns neighborhood represents a typology that’s relatively unique to Portland. We’re calling it the Twin House. This is a species of duplex, with a form resembling a contemporaneous style of single-family house. In this case, it’s a bungalow. It is basically two small bungalows, mirrored down the middle for bilateral symmetry. The more common stacked duplex is a fixture of cities across the country and was very popular in the first decades of the 20th century.

Typical stacked duplex, Kerns Neighborhood

Twin houses like this offer most of the benefits of single family homes: semi private yards, generous open space, lots of access to air and light via three window walls. They also have an interior parti that is basically that of a single family house with many examples, such as this one, having stairs leading to bedrooms upstairs, and a private basement for laundry and storage.

2233-40 NE Everett site plan.

This example is not a legal use on its site. It’s zoned R2.5, meaning 2500sf of lot area minimum is required per unit. This twin house is built on a smaller than standard lot (3,184sf), so it is a non-conforming use.  If it were on a standard 50x100 lot it would be legal.

Historic twin houses are typically rental duplexes, as opposed to what we call a row house, with fee simple or condo ownership, though this can and does occur on occasion.

We will xplore more examples of the Twin House in the near future.

 

41 NE Skidmore

Building Data:
Neighborhood: Humboldt
Year Built: 2017
Typology: Townhouse
Units: 3
Stories: 3
Site Area: 7,456sf  (est.)
Building Area: 6,800sf
FAR: 0.9:1
Density: 17.5du/net acre                              Zoning: R2.5
Is it Legal? YES

This is a fairly attractive variant on a popular 21st century typology, the townhouse with a ground level garage. In this case, two smaller townhouses bracket a larger one in the center. The two eastern units share a curb-cut which provides access to one-car garages. The western unit has a detached garage at the extreme northwest corner of the lot, where it fits nicely due to an irregular lot shape.

Like many infill typologies, this works much better on a corner lot, since the new sub lots can re-orient toward the long side and still face a street.

This developer resisted the urge to make the cars occupy most of the ground floor and make up the lost residential square footage with a third floor. The mini tower format certainly maximizes the amount of house the developer is selling, but it leads to a home with little to no relationship to the outdoor space, and leads to a lot of climbing stairs, which is less desirable for older residents, and irritating to just about everyone.

41 NE Skidmore site plan.

It’s noteworthy that this project was developed as condos. The three units sit on a single lot and the owner is listed as the Home Owners Association (HOA). This may be a result of the fact that land divisions to create new lots out of a larger parent lot take a long time and add cost and complexity to a project. 

 

5900-5920 N Albina Ave

Building Data:
Neighborhood: Humboldt
Year Built: 2014
Typology: Plex / One Story / Bungalow court format
Units: 6 (Pair of identical triplexes on separate lots)
Stories: 1
Site Area: 10,000sf
Building Area: 5,040sf
FAR: 0.5:1
Density: 26du/net acre                                 Zoning: R2
Is it Legal? YES

This project is the first attempt we’ve seen to replicate the 1920s single-story bungalow court format. There several great examples of the original prototype just north of here, along Albina Ave. There are a few caveats. This is actually configured as a pair of separate linear triplexes. They are on separate lots. Both lots are 5000 sf and are zoned R2a, which allows one dwelling unit per 2000sf of site area. The “a” overlay denotes Alternative Density Design Overlay, and it’s provisions likely facilitated the total unit count of 6 DU on 10,000sf.

6337 N Albina - Example of a typical 1920s courtyard building.

These triplexes represent a very attractive typology, from a resident’s point of view. Individual front doors give the units a home-like presence on the street, as opposed to an anonymous shared hallway in an apartment type structure. All units have at least two window walls and end units have 3. This particular development has small fenced private back yards. This makes this typology more attractive to families with children. Ideally, these buildings could link up and form a U-shape around a central courtyard.

We’d love to see more of this type of building, for all the reasons above. We’d also like to build a picture of the kind of parameters that would make it sensible to build this way. We wonder if perhaps so few of these buildings get built is because doing a single story apartment with no off street parking amounts to “leaving money on the table.” We have observed several similar sites redeveloped as three story