How They Pulled It Off: A Brooklyn Townhouse 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 towards 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 townhouse 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 townhouse 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 townhouse 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 townhouses in Brooklyn with this type of settling, but this one was exacerbated by several factors," says Segulja.