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Closeup photograph of tabby shows the dense layers of oyster shells that lend strength to the concrete
(Photograph by Michael Broam)

Tabby:
The Oyster Shell Concrete
of the Lowcountry

by
Dennis Adams
Information Services Coordinator

Tabby is a concrete made from lime, sand and oyster shells. Its origin is uncertain: although early documents record Indian burial vaults with walls made of oyster shells and lime, no such structures have survived. It is likely that Sixteenth-century Spanish explorers first brought tabby (which appears as "tabee", "tapis", "tappy" and "tapia" in early documents) to the coasts of what would become South Carolina and Georgia. Tapia is Spanish for "mud wall", and, in fact, the mortar used to caulk the earliest cabins in this area was a mixture of mud and Spanish Moss.. There is evidence that North African Moors brought tabby to Spain when they invaded that kingdom: a form of tabby is used in Morocco today and some tabby structures survive in Spain, though in both instances it is granite, not oyster shells, that is used.

According to Janet H. Gritzner, "the vast majority of tabby structures were located on the southern Atlantic coast. This distribution reflects diffusion from two primary centers or hearths: one at Saint Augustine, Florida, and the other at Beaufort, South Carolina. These centers represented the core areas for two separate traditions in tabby building. ... British-built tabby arising out of Beaufort, South Carolina, had a quite different history and distribution from that of Spanish origin." Although the British tradition began later (around 1700, upon introduction of the technques from Spanish Florida) than the Spanish (1580), it was less restricted. "Beaufort, South Carolina, was both the primary center for British tabby and the location of the earliest British tabby in the southeastern United States. It was here that the British tradition first developed, and from this hearth tabby eventually spread throughout the sea island district."

Gritzner doubts that there is any connection between the use of tabby by the Spanish at the Santa Elena site and the first uses of the material in British Beaufort about 120 years later.

Colin Brooker of the Historic Beaufort Foundation said that Beaufort County has the largest number of tabby ruins in the United States. The Foundation has placed the county's tabby structures on its endangered resources list. Mr. Brooker said that "much of the destruction that has taken place has occurred naturally. Tabby, by its very nature, is generally a poor quality material."

In the New World, Fort San Felipe, built in 1577 on what is now Parris Island, S. C., is an early example of tabby construction. The compound contained more than sixty tabby houses.

A pile of thousands of oyster shclls, with an inset picture of two shells seen close up
Oyster Shells: The Raw Material for Tabby
Photographs by Dennis Adams
(August 14, 2002)
  Early settlers found only trees and the raw materials for tabby (and none of the stones and brick-clay they had known in Europe) when they began building permanent structures in this coastal area . The Native Americans of the Sea Islands had left many heaps of shells, the accumulation of countless past oyster roasts. Builders extracted the lime by burning the oyster shells. They then painstakingly removed all salt from the shells and from the sand to keep the concrete firm and whole (the salt weakened the concrete mixture). The cleaned sand, a mixture of coarse and fine varieties extracted from sand pits, was added to the lime and shells to make the tabby concrete.

"Oyster shells," wrote Earl D. Dietz, "are primarily calcium carbonate. When they are 'burned' they are heated to a high enough temperature to decompose the calcium carbonate to lime (calcium oxide) and carbon dioxide, which dissipates in the air. The resulting lime mixed with the sand, the oyster shells and water reacts with the water, and to some extent the sand, to form a bond for the mixture. Thus Tabby is a concrete. Today, artificial tabby is made using Portland cement instead of lime and the resulting 'tabby'is stronger and more stable. In this area there are many driveways and walks made from the artificial tabby."

Todd Dickinson reported that in his research of the lime burning process, he found that "the books suggest burning 3/4 inch pieces of limestone or oyster shells in a kiln at 2,000 degrees F. Another source suggested that charcoal and lime be burned together". Experimenting with the process, Mr. Dickinson "roasted oyster shells for 5 hours on a gas grill at about 600 degrees F and they softened some. Then I roasted them for another 3 hours, then made a camp fire at the Eno River Festival, covered part with bricks and stoked the fire and shells for two more hours. Some of the shells got quite soft and a portion of them burned, and the ground shell reacted to a vinegar acid bath, so I guess that much lower temperatures will eventually result in producing the first step towards mason's lime". (Please note that this description is not intended to serve as a practical formula for producing tabby.)

Tabby was cheap to produce, but labor-intensive (the shells had to be thoroughly washed). It was probably not much slower, however, than other construction processes of the time: Georgian Thomas Spalding reported that his "people" could produce thirty cubic feet per day with enough work to "employ six hands for three days to compleat the rounds, mixing mortar one day and filling in two, thus making two rounds a week", even accounting for bad weather. Tabby construction required only unskilled laborers, not the more expensive carpenters (and sawmills) that lumber entailed.

Wet tabby was poured and tamped into a wooden form made of two parallel planks extending along the full length of a wall. The planks were tied together by crosspieces . The boards were moved up repeatedly as each layer of tabby dried (the imprint of the planks is often visible on finished structures), up to the desired height of the wall. To create a window or door space, builders placed a short plank across the inner and outer boards of the form and steadied it with two poles. Stucco overlays and scoring (to imitate brick patterns) were methods to disguise the humble tabby; the stucco also prevented the accumulation of moisture within the rough surface of the shells. Wood (for joists and lintels) and bricks (for corner columns, doors and windows) were often incorporated into the tabby structures, either during the pouring or when the mixture was still wet. Settlers also made individual bricks of tabby and used the cement to construct all manner of houses, farm structures, churches, fortifications, sea and exterior walls, fireplaces, tombstones, and other structures -- including an extant mill wheel made from tabby. Of only two remaining ruins of indigo vats in South Carolina, one is built of brick and the other, recently discovered in Beaufort County, was made of tabby (both date from the early 1700s). A report from 1775 mentions repairs to Fort Lyttleton’s "two tapis walls and a tapis breakwater wall."

Local use of tabby decreased after the Revolutionary War, until around 1805, when Thomas Spalding began using it on Sapelo Island, Georgia. Spalding's formula was "10 Bushels of lime, 10 Bushels of Sand, ten bushels of shells and ten bushels of water" to yield sixteen cubic feet of wall. He made some walls fourteen inches thick and "below the lower floor 2 feet; for the second story 10 inches -- beyond that (he) would not erect Tabby buildings." Spalding's one-story tabby home ("of the Ionic order") was raised four feet from the ground, measured ninety feet by sixty-five feet in depth, and stood "sixteen feet in the ceiling and 20 feet in wall.

Shells are exposed in the outer surface of the tabby wall at Fort Frederick
Close-up of tabby
wall at Ft. Frederick

(Photograph by
Michael Broam)
" It took 'six men, two boys and two mules (one white man superintending) two years to build the house'".

Although tabby was widely used throughout the Sea Islands, few buildings in Charleston were constructed of that material. Bricks were easy to obtain in that city.

Tabby walls may have helped to abate the disastrous fire that struck Beaufort in 1907. The January 21, 1907 issue of the Savannah Morning News reported: " The firemen made a brave fight against the fire, but the high wind caused it to get beyond their control very quickly. Then it was beyond their power to curb its progress. Not until a number of old buildings, constructed with tabby, a material made of sand and shell, had been reached by the flames could their ravages be stopped."

Tabby cement, a combination of oyster shells and modern cement mix, has been used to construct some local buildings in the 20th century


Beaufort County's Tabby Landmarks

Chapel of Ease (Land's End Road on St. Helena Island): The small chapel was built of tabby and brick from 1742-1747 for the Episcopal parishioners on St. Helena Island. On Sunday, November 4, 1861, the services at the Chapel of Ease were interrupted by a messenger sent by a Capt. Fripp: the Union invasion that would bring the Federal occupation of Beaufort was at hand.

A forest fire caused extensive damage in 1886, and St. Helena Episcopal Church now has custody of the ruins.

 

The door and window archways in the tabby Chapel of Ease on Saint Helena Island are reinforced with bricks
Photograph by Dennis Adams
(August 13, 2002)



The Sea Wall (Bay Street east of Carteret Street intersection, facing the Beaufort River): Although its age is unknown (estimates range from the time of the Revolution to the Civil War), it is an example of how tabby can withstand the elements (and salt water) once it has set and hardened.

Erosion and time have worn down the tabby walls of Fort Frederick. A low profile remains
Existing tabby walls of Ft. Frederick
(Photograph by Michael Broam)

Fort Frederick (On the Naval Hospital premises, Port Royal): The fortification was built in 1734 to replace the Beaufort Fort of 1706. In 1758, Fort Lyttleton in turn replaced Fort Frederick, which had already fallen into a state of bad repair and had been left undefended since about 1743. Only some of Fort Frederick's tabby foundations remain.

 

Standing high on Beaufort's Bay Street is the three-story Francis Saltus House. Pink paint decorates its tabby exterior

Photograph by Dennis Adams
(November15, 2006)

  Francis Saltus House (formerly known as the Habersham House, 802-806 Bay Street, Downtown Beaufort): Built in 1774, the building has served as a customs house, hotel and, during the Federal occupation of Beaufort during the Civil War, a commissary store. The Francis Saltus House was constructed of tabby and old English bricks.
Tabby Manse (1211 Bay Street, Downtown Beaufort): Built by Thomas Fuller in 1786, the house has exterior tabby walls two feet thick (finished with stucco). Held by wooden pegs, its structural timbers measure twelve inches thick. Richard Fuller (1804-1876), the famous Baptist clergyman, was one of the builder’s seven children.  
The massive tabby walls of the Tabby Manse present a graceful and delicate facade
Photograph by Dennis Adams
(August 14, 2002)


Remnants of the foundation of the Gold Eagle Tavern (along the river at New and Bay Streets): The tabby foundation of a structure developed continuously from 1785 until the 1930 was the site of the famous Gold Eagle Tavern (demolished in the late 1960s). The existing residence was built after the demolition of the original building. The last private resident of the original house was Kate Gleason, the famous business promoter and philanthropist.

Elizabeth Barnwell Gough House (Washington Street): Built around 1780.

The Tabby Wall in Laurel Bay, located in the woods near the playground by Bay Circle in the military housing area. It is approximately100 feet long, with the remains of several rooms.

Hilton Head Island Sites include: The Stoney-Baynard Ruins in Sea Pines Plantation; the ruins of the The George Edwards House; and foundations of chimneys on a row of slave quarters in Drayton Plantation (next to Barker Field).

Other Beaufort County Sites include: The Edwards Tabby Ruins (ca. 1790) on Spring Island Seacoast Packing Company (also called the "Pickle Factory") on Grayson Street, Beaufort, Old Jericho Road in Burton, Beaufort's Northwest Quadrant Neighborhood, The Seabrook Community (off U. S. Highway 21, near Whale Branch River), The former Beaufort County Jail on King Street, Tabby Structures on Spring Island, and The Remains of the B. B. Sams Plantation House on Dataw Island, built by Sams and his brother, Reeves (remnants of housing for family and slaves, farm buildings and the foundation walls of a chapel). Reeve Sams' buildings were destroyed in the mid-1800s, when a hurricane washed away nearly a hundred acres on the Morgan River side of the island.

Concrete and Cement: What's the Difference?

Adapted from e-mails of Earl D. Dietz,
Emeritus member of the American Ceramic Society.
(January 9 and February 16, 2006)

The cement in tabby is the lime, sand and water that binds the oyster shells. Tabby is a building material.

Today's concrete is composed of Portland cement, sand, aggregate and water. Depending on the end use the aggregate can be rather fine crushed stone or rather coarse crushed stone. Portland cement is made by heating together minerals that contain the oxides of calcium, aluminum and silicon. These react to form compounds of calcium alumino silicates. All chemically bonded water is removed during the heating or burning. When the Portland cement is mixed with water (and the sand and aggregate) it hydrates, or forms a compound with water that is very strong.

Mortar, sometimes called cement is a mixture of Portland cement, sand and water. Mortar is used between bricks and other building materials.

Sources:

  • Broam, Michael. Photographs cited above.
  • "County Boasts Many Tabby Sites" (Staff Report). The Beaufort Gazette. September 27, 1999; pages 1-A and 2-A.
  • Dickinson, Todd. E-mail message of July 6, 1999.

  • Dietz, Earl D. E-mails of January 9 and February 16, 2006.

  • Dimock, A. W. "The Fleet is Upon Us", in Port Royal Under Six Flags by Katharine M. Jones. Bobbs-Merrill, 1960.

  • Gritzner, Janet H. "Distributions of Tabby in the Southern United States A Geographical Perspective." February 1998. Georgia Department of Natural Resources Historic Preservation

  • A Guide to Historic Beaufort. The Beaufort Historic Foundation, 1970.

  • Historic Resources of the Lowcountry. Lowcountry Council of Governments, 1979.

  • Langley, Lynne. "Symbol of the South: Spanish Moss is Neither". Post and Courier ( Charleston , S. C.) of May 16, 1996.

  • Lepionka, Larry. "The Nature and Origin of Tabby". The Archaeological Society of Callawassie Island (Bulletin), August 1983.

  • Spieler, Gerhard. "Low Country Tabby". The Beaufort Gazette of September 21, 1972.

  • Van Pelt, Rita. "Tabby: The Sea Island Cement". Beaufort: Land of Isles magazine, Winter 1978.

  • Wilson, M. Ed. "Troops Sent to Beaufort to Hold Negroes in Check". Savannah Morning News of January 21, 1907.

 
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