This project was a full townhouse renovation that included a penthouse roof addition and a 3-story addition on the back. The project presented a number of unique challenges. First, the bulk of the structural work related to the addition was done during the winter season. Also, the scope of the project included an elevator requiring basement excavation to a level below the water table.
RESULTS & SOLUTION
To solve the first challenge, we decided to construct the building addition structure while maintaining the existing roof and weather envelope in place. After the new envelop of the expanded building was made weather tight, we then removed the original roof. This allowed us to keep the water out and the heat in while working inside throughout the winter. To excavate for the elevator pit, we needed to pump out the water while taking care not to undermine the foundations of both our structure and the building next door. Once the excavation was complete, we lined the entire pit with special clay panels that keep the pit watertight.