109-111 Pine Street, Phila., PA.

About

GTA provided underpinning observation, excavation oversight, and structural monitoring services for the  historic three-story brick residence at 109–111 Pine Street in Philadelphia’s Society Hill neighborhood. The  project included installation of a new French drain, dual sump-pump system requiring approximately 200  linear feet of excavation, with trenching at 16 inches wide by 16 inches deep along the interior slab and  an additional 12-inch-by-12-inch underpinning cut beneath existing foundation walls, totaling an  estimated 23 cubic yards of excavation. GTA observed underpinning excavations ranging from 12 to 18  inches below the existing footings, confirmed footing conditions, and documented reinforcement. GTA’s  licensed Special Inspectors provided continuous observation during underpinning and excavation to verify  stability of the existing masonry walls and ensure compliance with IBC 2018 and the City-approved  amended construction documents. This project highlights GTA’s expertise in managing sensitive urban  foundation work and protecting historic structures during basement renovations and structural  improvements.