8,000 Boston Buildings at Risk of Structural Failure

Boston's century-old homes look lovely from the outside, but hidden dangers lurk inside.

Boston faces widespread risk to building foundations from rotting underground timber pilings. Approximately 8,000 structures on reclaimed land from the mid-1800s to the early 1900s could potentially be affected, according to a Boston 25 News report.

The Boston Groundwater Trust, an organization founded by the Boston City Council in 1986, plans to deploy automatic groundwater sensors this spring to improve monitoring and early detection of groundwater level changes.

“We work with the entities that own the sewers, the drains, and the tunnels, making sure that those are tight, that those don't leak,” said Christian Simonelli, executive director of the Boston Groundwater Trust, in a statement shared with Boston 25 News.

The rotting problem results from exposure of the wood pilings to oxygen, which allows microbes to rot them. Over time, this rotting can lead to foundation collapses.

Repairing the damage could cost homeowners upward of $200,000.

“Depending on the size of the building, depending on the number of wood piles underneath the building, it could be anywhere from 12 to 18 months,” Simonelli said.

According to Boston 25 News, many of Boston's most recognized landmarks have required foundational work over the years due to these risks. The Boston Public Library, Trinity Church, and Old South Church are among the structures that have had their wooden pilings repaired or replaced over the last century.