Fort Pulaski Terreplein Excavation

Terreplein work 1930s

NPS Photo

History of Repair

Previous excavation and repair work on the terreplein was completed by the Civilian Conservation Corp (CCC) and the Public Works Administration (PWA) in the 1930’s. Projects consisted of terreplein fill being excavated, masons rebuilding the latticed brickwork over the lead, and damaged abutment walls being repairs. Waterproofing efforts were also made.

What is the Terreplein?

The terreplein is the elevated area at the perimeter of the fort above the casemates. An intricate drainage system is associated with the casemate ceilings. This system includes a layer of lead over the structure of the casemates. An interior gutter runs between the casemates, which is formed by arched brick. These arches were built over the low point of each roof, which sits between each casemate. Oyster shell was originally placed over the sheet lead prior to the earth being added. The earth forms the terreplein surface. The terreplein is largely covered by grass.

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Water damage to Casemate from leaking Terreplein drainage system

NPS Photo

Why are Repairs Needed?

There has been considerable damage at Fort Pulaski, which has been caused by decades of water seeping through the terreplein’s punctured lead sheeting and into the casemate below. In addition to the cracks and the loss of mortar in the masonry created by the water intrusion, mildew and lichens are growing around these constantly moistened areas and rotting of the wood casemate floors has been recorded. Future water damage could result in a loss of historically significant material if original bricks begin to loosen and historic mortar continues to fail.

Repairing the Terreplein

NPS Photo

Repairing the Terreplein

Currently, there are 5 locations that are in need of excavation and repair. Preservation efforts for these locations have been undertaken by NPS staff and members of the Traditional Trades Apprenticeship Program (TTAP.) Excavation is done by hand, as well as with an excavator located on the terreplein. For the purpose of documentation, the brick arch is dismantled and labeled in order to rebuild it in to its original state. The brick is then removed and stacked. Upon dismantling, the gutter is then cleaned out and assessed to locate the damaged area for repairs. Damaged lead sheeting is removed, and any damaged mortar underneath is chiseled out for repair. The mortar joints of the brick in the casemate underneath that have sustained water damaged are chiseled out, and the brick is cleaned. Mortar is repaired, providing a water-tight seal to prevent future leaking. The lead above is repaired, and the brick arch is rebuilt. The original loose oyster shell used as filtration, has been replaced with bagged oyster shell.