A Modern Spin on a Home Addition

Instead of adding a room onto their home, Celestino Piralla and Cornelia Stumpf added a modular 320 square-foot structure that functions as an office with mid-century modern design.


Photography by Richard Johnson

Photography by Richard Johnson
By: Elizabeth Beeler

When Savannah, Georgia designer Celestino Piralla and Public Relations maven Cornelia Stumpf of CSPC Consult Design were looking to find the ideal space for their new office, they didn't have to look very far. The couple sought a home-based office, but was deterred by the thought of altering the footprint of their mid-century home in order to accommodate the extra space. "Additions tend to compromise the original nature of any building," says Celestino.

Instead, they opted to build a new structure. Conveniently located just a few yards from their back door, the outbuilding makes the most of an otherwise unused space.

In terms of design, decisions were easy. Modernist enthusiasts without reservation, Celestino and Cornelia knew they wanted a practical structure dictated by purist principles.

The couple explored modular structures because they're easy to construct, quickly built, and sustainable over time. In addition, modular units are typically less labor intensive, which ultimately results in a more economical price point.

Celestino and Cornelia collaborated with Phoenix-based ASUL and found a modular plan adaptable to suit their needs and site-specific requirements. "With prefab structures you have little flexibility," says Celestino. "But these modular outfits make a lot of sense."

Main steel framework along with bare exterior walls and roof components were manufacturer provided, leaving Celestino and Cornelia with opportunity to complete the design-build project using locally sourced materials and labor. "About sixty percent of pre-fabricated structures come from the West coast," says Celestino. "But the ASUL process allowed us to purchase the drawings and build locally, reducing our carbon footprint significantly."

With its savvy design, the couple's single-room 16 x 20-foot structure with a cantilevered 16 x 8-foot covered porch lives large, providing ample workspace. Initially, the office was intended to be built at grade level. However, the site's location was later determined to exist within a flood plain.

Mid-Century Modern Prefab Addition

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In order to meet insurance and permit requirements, plans were easy adapted with the flexible building approach. Six-foot steel pilings were added underneath, permitting the simple structure to hover above ground like a tree house. "There's an organic language in modernism," says Celestino. "Modern structures are highly adaptable to any environment."

Once approved by the city, the stoic outbuilding referred to as the "Think Tank" was constructed in just six weeks. Situated with large ceiling-to-floor windows on the eastern façade and smaller counterparts placed high on the western elevation, the steel frame building takes advantage of natural light without intruding on the privacy of neighbors.


A retro conference table makes a stylish statement. High-backed wooden chairs with orange seat cushions reiterate the room's color scheme.

A retro conference table makes a stylish statement. High-backed wooden chairs with orange seat cushions reiterate the room's color scheme.

Galvalum exterior cladding chosen for its durability, low-maintenance, and low price point makes a contemporary statement from every vantage. "For cleaning, the exterior cladding is simply hosed down," says Celestino. Maximum insulation in wall, floor and ceiling cavities along with recessed LED porch lighting and double paned, argon windows ensure utility bills are kept minimal.

Weather-resistant gypsum board clad beneath the main structure and porch awning offers maximum protection from Savannah's moist climate. Finishing off the look, a steel staircase offers easy access, and unwavering strength.

On the interior, Celestino and Cornelia maintained the building's smart design. White walls and ceilings with a connection to the exterior through the abundant windows allow tight quarters to feel more spacious. Underfoot, carpet tiles made from recycled materials create a geometric pattern.

Dual desks, filing cabinets, and a conference table and chairs outfit the space with work place essentials, while a hip pendant light adds a warm glow after dark. Industrial shelving anchors the room from two sides, housing an extensive collection of books and objects d art. Sleek solar shades adorn the windows, allowing natural light to fill the room while filtering direct sunlight.

Visually, the modular outbuilding distinguishes the Stumpf residence from the neighboring residences. But in terms of efficiency, the "Think Tank" sets a new standard. With plans to go completely solar in the next decade, this state-of-the-art outbuilding will surpass all expectations. "We have not found any disadvantages," says Celestino. "This structure lends itself perfectly to its intent."

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