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120 Fulton Street Condominiums

120 Fulton Street in Boston, Massachusetts, also known as the McLauthlin building, was used as a manufacturing facility until it was converted to condominiums in the early 1980s.  During the conversion, the height of the building was increased by the addition of two stories. 

A short time after the conversion, physical evidence suggested that the building was settling in several areas.  Settlement was traced to a variety of causes, but for the most part was believed to be a result of compression of timber framing and the possibility that the increased loads due to the addition of the two stories were causing the pile foundation, which had not been supplemented during the conversion of the condominiums, to settle.  At that time, foundation movement was considered to be a minor issue.  We perceive the original due diligence efforts by the designers supported this approach.  Timber framing compression issues were solved with additional supports and a settlement monitoring program was established to periodically view the grades of the building.

Over the next eight year period, settlement continued at a variable non-alarming rate throughout the footprint of the building.  The monitoring program indicated that settlement reached a point where wall cracking became fairly constant and more pronounced, and doors began to bind where no problem had existed previously.  At that point, the trustees commissioned a review of settlement history and as a result, prepared a program to determine the cause for settlement.  The settlement monitoring program was extended to include a test pit exploration program of certain areas of the building to view timber piles beneath the structure.  The test pit explorations revealed varied foundation conditions such as sections of foundation bearing on rock walls and/or masonry walls, and pile conditions which varied from timber piles in good condition with capacity remaining to timber piles with no capacity remaining.

The results of the test pit excavations dictated that those piles with no capacity remaining be repaired using a combination of pile section replacement (removing a section of the deteriorated wood pile and installing a concrete encased lally column), screw piles (which are literally screwed into the ground), and resistance jacked piles (which are driven into the ground until a certain level of resistance is met).  During the repairs, a remarkable difference in water level below grade was recorded.  Knowledge that water levels within parts of the North End of Boston had been reducing and there was no recharge program in place, it was determined that a site recharge system would be installed to recover roof drain water and direct it to the underground.  In itself, the recharge system is not a solution, but it will help to stabilize the groundwater level beneath the structure to some degree and to expand the longevity of the piles which have remaining capacity.  Those piles which have been repaired or supplemented have been done so to anticipate a water level that will protect the piles for the foreseeable future.  In addition, the trustees have implemented a regular monitoring program for groundwater level and settlement.