Welcome to How They Pulled It Off, where we take a close look at one particularly challenging aspect of a home design and get the nitty-gritty details about how it became a reality.

When architects Margot Otten and Doug Segulja first set foot in a 1901 townhome in Brooklyn’s Park Slope neighborhood, they could tell immediately that something was off. “As soon as you walked in, you could feel the house pulling you toward the back,” recalls Segulja, who leads Brooklyn firm OSSO Architecture alongside Otten. “It was so tilted, it felt like you were on a boat,” adds Otten. “If you were to put a ball at the front of the house, it would literally roll straight down to the back.”

The culprit for this major tilt? The townhome was sinking. “We had a geotechnical engineer do soil tests at the front and back of the house, and he told us that the back of the property was fill, it was not natural soil,” explains Otten. Tests revealed the back of the lot contained old ash from coal-burning furnaces that had been dumped over a century ago, while the front of the townhome sat on much more stable soil. “This area is very close to a terminal moraine where glaciers melted tens of thousands of years ago, and that left an uneven landscape with pits where the ice had melted,” says Otten. “People used to fill them with ash and garbage to make even ground.”

The homeowners bought the townhome and had been living in the parlor unit and basement for a decade while renting out the upper units. However, after having their third child, they knew it was time to expand. They decided to take over the entire townhome and finally fix the sloping floors. “They also really wanted to have a space on the roof to take in the views, and had desires to build an additional story on top,” says Segulja.

Adding this extra weight meant the designers needed to do more than replace sloping floor joists, so they set out to reassess the townhome’s foundation. The original building sat atop wooden piles, but the test pits revealed the wood piles had rotted over time. Plus, the addition of a small extension to the building in the ’60s created added weight that increased the sinking. “We’ve seen a lot of town houses in Brooklyn with this type of settling, but this one was exacerbated by several factors,” says Segulja.

The first step was to figure out what the structure needed in order to accommodate the renovation. Besides adding the additional floor and roof terraces, the owners also wanted to rethink the interior layout to better connect all the floors. The original floor plan had a tight stair running up the back of the building that connected to each apartment, but the designers decided to relocate the stair to the center of the townhome for better flow and to draw in more daylight.

How they pulled it off: Stabilizing the foundation and leveling the floors

Once the designers landed on a general design scheme with the clients, they consulted with a geotech engineer and structural engineer to assess the soil conditions and foundation needs.
“The geotech dug three-by-three-foot test pits to inspect the low point of the foundation and make sample borings of the soil,” explains Segulja.
Because of the soil conditions at the back of the property and the likelihood that the building would continue to settle in the future, the engineers recommended new metal piles be added to stabilize the foundation. “We put in these skinny metal piles that run thirty to forty feet down into the earth, through all of the ash, to more stable soil,” says Segulja.
All told, the team added 32 helical piles beneath the existing foundation walls. Along with the pressure of the surrounding earth, the piles give enough support to stabilize the building and prevent it from sinking even further.
After the new piles were installed, the team proceeded with demolition of the existing floors, creating a renovated home with level floors and a plumb rear facade.

While undertaking a project of this magnitude is not for the faint of heart, the owners decided to move forward after looking at other properties and realizing they would get much less for their money than if they were to renovate their existing home. “They already owned the town house, which was to their advantage, and they have five floors,” says Segulja. “If they had bought a new finished place, they probably would have gotten about half that square footage.” Otten agrees. “It’s an intimidating task up front, but for the client who’s willing to take it on, you get a lot more for your money, as long as you can be patient, flexible, and adaptable.”

Besides opening up the main floor with an open-plan living/dining/kitchen space which connects to a back deck and garden, the other major change to the layout came in the form of the fifth-floor penthouse extension. The space opens to a front and back terrace, and contains a small kitchenette. “The penthouse works fabulously for parties, and the house now has so many spaces for people to congregate,” says Otten. “The open stair also helps you hear where the kids are in the house, no matter what level you’re on.”

The powder room contains a custom stone sink in lilac marble sourced from ABC stone. “The owners said from the beginning that they wanted to keep the original purple front door,” says Otten. “We leaned into that and pulled elements of purple throughout the house, including the marble with lilac veining in the powder room and kitchenette.”" layout="" credit="Photo by Erik Bernstein" photoUserId=""/>

In the end, the townhome is ready for its next chapter as a family home. Stabilizing the foundation was one of the more challenging technical aspects of the renovation, which certainly gave the owners sleepless nights, but the final product was worth it. “I’ve known the owners since 2008 and we’re still good friends,” says Otten. “There’s something so special about this house, and it’s definitely helped inform how we approach future projects with similar issues.”

Project Credits:

Architect of Record: OSSO Architecture / @ossoarchitecture

Builder: KF Restoration

Structural Engineer: Severud Associates

Civil Engineer: Pillori Associates

Landscape Design: Hannah Edmunds Gardens

Photographer: Erik Bernstein

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How They Pulled It Off: A Brooklyn Townhome Was Sinking, But They Brought It Back to Life