Repointing 25 million bricks: preserving Fort Pulaski's masonry

Damage from a failing drainage system. NPS photo.

Fort Pulaski, on Cockspur Island at the mouth of the Savannah River in Georgia, is built of an estimated 25 million bricks. Masonry is most of the fort and part of nearly every system in it, and time, weather and the wrong mortars used in past repairs have loosened its joints and damaged its brick. The National Park Service is working through the fort casemate by casemate to put that right.

The work, step by step

1. Inspect and document every casemate before any work begins — a record that will guide future repairs too.
2. Prioritise: the worst-damaged casemates, and those most likely to deteriorate further, come first.
3. Clean with a gentle biological solution that removes dirt and growth from the brick.
4. Chisel out failing mortar.
5. Repoint with a historically appropriate mortar mix; any replacement brick is matched as closely as possible to the old.

The same treatment goes to the masonry piers that support the floors beneath the decking boards. The work is done by Park Service staff and interns of the Traditional Trades Apprenticeship Program (TTAP), which trains people in the crafts historic buildings depend on.

Repairing the moat wall from a boat. NPS photo.

A long line of repairs

Traditional Trades apprentices repair brick damaged by water. NPS photo.

Sources

Written from "Fort Masonry", National Park Service, Fort Pulaski National Monument, a work of the United States government in the public domain.