How They Pulled It Off: A Brooklyn Townhome Was Sinking, But They Brought It Back to Life
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."
In Brooklyn, OSSO Architecture renovated this 1901 Park Slope townhome, which was literally sinking.
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."
Because the owners wanted to add an additional level including a family room and roof deck to the top floor of the townhome, the architects needed to stabilize the foundation to accommodate the additional weight.
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.
After discovering the townhome was sloping due to unstable fill at the back of the property, the designers set out to stabilize the foundation and began a gut renovation inside.
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.
The townhome had a small addition at the back which was added in the 1960s, but the designers decided to remove it in favor of creating an outdoor deck right off the relocated kitchen.
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.
The designers decided to relocate the stair to the center of the townhome, allowing more natural light to enter the core of the building via a skylight overhead. A custom oak handrail fabricated by Paragon Woodworks runs from top to bottom.
New engineered oak floors and oak cabinetry lend a warmth to the interiors, especially the new open living area containing the kitchen, dining, and living area on the main floor. The glass pendants over the island were made by the father of one of the owners, who owns Pablo Glass in Woodstock, New York.
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."
In the primary bath, cedar wall paneling complements an oak vanity with a custom concrete sink and counter. The floors are slate tiles by Cle.
The tub in the primary bath is by Agape with a faucet from Watermark.
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 penthouse level contains a new kitchenette and opens to a front and back terrace.
The countertop in the kitchenette is a lilac marble from ABC Stone, and the cabinetry is custom oak. The faucet is from Waterstone.
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."
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
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