• The dramatic double-vaulted ceiling and five-foot-diameter windows found in the second-floor bedroom inspired the project’s affectionate nickname. - photo by Chase Daniel

An East Austin ADU engages simple materials for a uniquely playful design.

Project Birdhouse
Location Austin
Client/Developer/Builder Digs ATX
Architect North Arrow Studio
Design Team Francisco Arredondo, AIA, Bobbie Behm
Structural Engineer Greenearth Engineering
Styling Ben Newman Studios
Photographer Chase Daniel

Perched amid the branches of three aging pecan trees, a birdhouse of unusual size overlooks East Austin’s Chestnut neighborhood. Sharing its residential lot with a bungalow built in 1939, the Birdhouse is an 885-sf rental home designed by North Arrow Studio. Despite its small footprint and limited material palette, this house is simultaneously fantastical in its design and grounded in its connection with the site. A study in simplicity, the Birdhouse explores what it looks like when a rental house is treated like a forever home. 

The Birdhouse is one of many small-scale residences that line the alleyways of East Austin. Concealed from view but deeply embedded in the neighborhood culture, these accessory dwelling units (ADUs) offer the opportunity for renters to live in single-family residential areas without the stipulation of homeownership. ADUs have become a way to provide affordable housing throughout Austin, but they must be integrated into established neighborhoods with great care; showing respect for the existing aesthetic and culture of an area can mean the difference between acceptance and anger from longtime neighborhood residents. 

As a longtime member of the Chestnut community herself, the owner of the Birdhouse outlined project goals that responded to common neighborhood complaints about ADUs. Her first goal was to ensure that the new building fit in with the surrounding neighborhood, taking inspiration from the shapes and materials of East Austin. The second goal was to work around the three protected pecan trees on the site, incorporating them into the design without disrupting their root systems. Her third goal involved the use of materials that would make the house easy and inexpensive to construct, as she would be overseeing the construction process herself. Lastly, the Birdhouse needed to look and feel like a home, not a bland rental property. 

Balancing all these goals required that the house be, according to North Arrow Studio principal Francisco Arredondo, AIA, “an exercise in simplicity—of materials, of layout, and of massing.” The design team curated a limited palette of materials and forms that would characterize the Birdhouse, choosing components that were inexpensive, durable, and easy to install. This unique but simple design language was inspired in part by the ancillary structures scattered throughout the Chestnut neighborhood, including garden sheds, carports, and garage apartments. Corrugated metal is ubiquitous amongst these types of buildings, as it is affordable and nearly indestructible. The Birdhouse is completely enveloped in this material, which was selected by the architects for its sustainability and resilience. In addition to being recyclable, corrugated metal is surprisingly energy-efficient. Using the same material for the walls and roof also meant that only one kind of tradesperson was needed to construct the envelope, reducing construction costs and simplifying the assembly process. 

To break up this monolithic exterior, the architects introduced another simple but unconventional staple: circular windows. Arredondo explains that the main challenge of the project was “getting the most out of the least” through their design choices. By making the swap from rectangular to round windows, the designers imbued the project with a sense of whimsy and sophistication without significant additional costs. The circular windows became a cornerstone of the project, inspiring its name and emphasizing its connection to the nearby trees. 

The site’s three protected pecan trees were incorporated into the design process from the start. The design team developed a simple L-shaped floor plan that avoided most of the trees’ critical root zones. Where the slab ran the risk of disrupting the roots of the nearest tree, it was cantilevered to avoid any potential damage. The L-shaped plan also creates an outdoor courtyard focused around one of the pecan trees, making the tree central to both interior and exterior spaces. 

The City of Austin restricts the square footage of ADUs, limiting them to just fifteen percent of their lot size. This rule often results in interiors that feel claustrophobic—the result of designers trying to cram traditional layouts into nontraditional spaces. The architects at North Arrow Studio wanted the Birdhouse to have a spatial flow more appropriate for a modern, flexible lifestyle. They sought to strike a balance between open and closed-off spaces in the house but needed additional square footage to do so effectively. Lacking the ability to expand outward, the design team looked upward for a solution. Their use of the attic space as a second floor allowed them to add another bedroom, bathroom, and closet without encroaching on the carefully curated spatial balance established on the ground floor. This strategy grants the occupants of the Birdhouse something most ADUs lack: breathing room. 

Because of limited space, many potential problems in the Birdhouse are solved by objects or spaces with dual functionality. The entryway, for example, includes a step down that both defines the threshold and accommodates the site’s grade change. The living room features a retractable garage door that functions as a window when closed but expands the space for indoor-outdoor living when open. The kitchenette wraps around the staircase to utilize the oft-ignored space underneath the stairs as a pantry. Each space also has a connection to the outdoors, which helps make the small spaces feel larger; the kitchenette and downstairs bathroom each have three round windows—custom-made by a local steel fabricator—while the living room looks out to the courtyard through a fixed window and swing door. 

In the hallway, a curved polycarbonate wall admits natural light through its semitransparent surface. Using polycarbonate—typically seen in greenhouses and sports facilities—to create the Birdhouse’s largest window dramatically reduced material costs. At the end of the hallway, the polycarbonate curves playfully into the first-floor bedroom, referencing the round windows above. The curved wall also allows the house to step back from the nearest pecan tree and give its roots more space to grow. The curvature takes advantage of the polycarbonate sheeting’s material properties, which make a curved window possible without highly skilled custom manufacturing or installation. In the bedroom, natural light filtering in through the polycarbonate window illuminates a double-height space with a steeply slanted ceiling. This unusually high ceiling offers the potential for occupants to transform the bedroom into a partially lofted space. Throughout the project, the design team looked for opportunities like this to expand the functionality of each space. 

The design team’s spatial creativity is on full display on the Birdhouse’s second floor. The upstairs bedroom is characterized by a double-vaulted ceiling and a trio of large circular “birdhouse” windows. The ceiling height dips below five feet at the corners of the bedroom, increasing the permissible floor space. (Under city code, the space beneath these low ceilings does not count towards the ADU’s total square footage.) The ceiling vault and the three five-foot diameter windows ensure that the space feels bright and open despite its low corners. One of these windows serves as the required egress for the second floor and underwent several iterations before being custom-fabricated as a swing window. 

Ceiling height also dictated the layout of the upstairs bathroom and closet. In these spaces, the primary part of the room was oriented towards the ceiling’s high point, while storage and shelving were placed under the low point. The ceilings in these spaces are so low that only a fraction of their floor space counts towards the ADU’s overall square footage, but their layouts ensure that they are still fully functional. 

Most of the fixtures and finishes in the Birdhouse are secondhand or upcycled products, each hand-picked by the client. She chose finishes that enhanced the character of each space, such as the brightly colored tiles that grace the walls of the bathrooms and kitchenette. Where upcycled products were not an option, low-cost alternatives were used: An inexpensive expanded metal handrail defines the staircase, giving the space an industrial yet refined look.

Many developers view rental properties as transitional spaces, giving little thought to the mental and physical impacts of their designs. In contrast, the Birdhouse prioritizes its occupants and seeks to make the rental house feel like a home. The unique design language of the Birdhouse, visible both inside and out, gives the rental a distinct sense of place. The project has had two tenants so far, and both have expressed a feeling of ownership that distinguishes the Birdhouse from other rentals. “It’s really easy to find examples of amazing architecture when you have a lot of time and money and resources,” notes Arredondo, “but you don’t find examples of that when it comes to a ground-up rental property.” North Arrow Studio has completed several other ADU projects, but the design team notes that a cookie-cutter approach is not suitable for these residences. They view the Birdhouse as proof that ADUs can be inexpensive, easy to build, respectful of their surroundings, and full of personality. Being able to successfully meet each of these goals makes the project, according to Arredondo, “a bit of a rare bird.”  

Abigail Thomas works at McKinney York Architects in Austin.

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