Byline: Gordon Jackson, Times-Union staff writer
CUMBERLAND ISLAND -- Some historic structures on Georgia's largest barrier island are getting a new look by workers using techniques hundreds of years old.
The structures on Cumberland Island all have one common feature -- they contain tabby, an old-style cement made from lime, oyster shells and sand. The most recent tabby project is a wall surrounding the Greene-Miller Cemetery near the Dungeness ruins at the south end of the island.
The 200-year-old wall had crumbled in places and National Park Service workers on the island wanted to repair the barrier surrounding the graves as authentically as possible to give visitors a true idea of how the cemetery looked after it was built, said Andy Ferguson, a management analyst on the island.
"Our maintenance staff has spent a long time learning how to re-create tabby," Ferguson said.
Tabby walls were popular when they were originally built because they were porous enough to release moisture from inside a building, while giving settlers protection from the elements, Park Service officials said.
Tabby also was a popular building material because it was inexpensive. Old oyster shells left in mounds by American Indians in coastal areas in the Southeast were mixed with sand to make tabby structures by early settlers.
The estimated 35 remaining tabby walls and buildings on the island, all built more than 100 years ago, were constructed by settlers who baked oyster shells in a kiln at high temperatures for as long as 18 hours, said Rick Hagford Jr., a maintenance worker for the National Park Service.
The shells are then mixed with hot water, which dissolves them into a bubbling paste as they're carefully stirred. The paste can be stored in a sealed container for years until the sand and more oyster shells are added to make tabby, Hagford said. …