The Flats at Southside Works, Pittsburgh, PA, 15203. Bedrooms: 1-2. The Soffer Organization is pleased to announce its latest residential development,The Flats at Southside Works! This one-of-a kind apartment community of 83 units,features a very innovative design and a European style that exceeds expectations.The Flats at Southside Works are located at 2635 East Carson Street and offer one bedroom and two bedroom/two bath flats or loft units, with 27 different floor plans to choose from.