When Frankie Mastromarco and his wife, Andrea, bought a three-bedroom property in Northern Liberties in 2007, it was just a shell.

"We designed and rebuilt the home from what was just four exterior walls and a roof," he said.

Today their investment property features a newer eat-in kitchen with polished granite counters, tin back splash, stone flooring, and high-end stainless steel appliances.

Yet Mastromarco said his favorite features in the home are not in the gourmet kitchen. "I would have to say [it's] the city grate bridge which leads you across the lower level into the home," he said.

The lower level is currently being used as a family room, with the three bedrooms situated on the second and third floors.

The property also features two bathrooms, one of which includes a reclaimed sewing machine that has morphed into a sink.

Mastromarco said the property history originally enticed him and his wife. "The home was originally built as servers' or maids' quarters for the seven-bedroom estate in front of it," he said.

The couple has been living in the neighborhood for over a decade, making a living by flipping properties.

"We've bought, sold, developed and maintained multiple properties in the last 15 years," Mastromarco said.

Recently, the couple made the difficult decision to list the property for sale. "This home is my baby and has excellent rental history," Mastromarco said.

But ultimately, the decision came down to a need to put their assets into new work.

"We have plans for two upcoming projects, and it is just time to cash out," he said.

The home is listed by the Somers Team for $349,900.