Frantom to Present on Bousillage Earthen Construction Technique

Buard-Wells House in Natchitoches, Louisiana after west wall render repair and limewashing applied.  Notice bousillage (clay and moss infill held in place by sticks called rabbet or barreaux) is only the infill system; the structural support is provided by large wood posts and sills that are mortised and pegged together in joined panels. Photo by Marcy Frantom.

Buard-Wells House in Natchitoches, LA, after render repair and limewash applied. Photo by Marcy Frantom.

Friend of NCPTT, Marcy Frantom, will present a paper on historical French earthen architecture from the Cane River National Heritage Area at Earth USA 2013, an international conference in Santa Fe, New Mexico.  The Heritage Area, located south of Natchitoches, Louisiana, between I-49 and the Red River, was set aside by Congress in 1994 to celebrate the confluence of American Indian, French, Spanish, African and American cultures. Frantom will discuss a construction method called bousillage, brought to Louisiana by colonists from the Normandy region of France and later modified by Native American and African building traditions.

According to Frantom, the bousillage tradition survives in numbers only in Louisiana, mostly Natchitoches and Pointe Coupee near Baton Rouge, and the St. Genevieve Historic District in Missouri. In 1994, she established a small business, Quality Finish, in part to meet a need for preservation skills in bousillage and limewash repairs at the Cane River Creole National Historical Park and other historic properties.  Frantom draws from personal interviews, vintage household product recipe books, scholarly articles, and materials testing to discover better methods to conserve finishes or recreate them.

Bousillage construction incorporates a wooden framework, known as colombage, consisting of a series of hand-hewn cypress timbers joined together with mortises, tenons, and pegs.  These timbers are filled in with a mud and Spanish moss mixture (bousillage) held in place with small sticks, called rabbet or barreaux.  After the mud and moss walls dry, they are coated with a clay and animal hair render or with limewash to protect them. Later, when cut nails were available, bousillage was clad with wood siding to prevent the walls from requiring frequent repair.

Retted (cured with outside bark removed by burying or cooking) Spanish moss and unretted Spanish moss often appear together in original bousillage material as in this photo of the Buard-Wells House.

Retted (cured with outside bark removed by burying or cooking) Spanish moss and unretted Spanish moss often appear together in original bousillage material as in this photo of the Buard-Wells House. Photo by Marcy Frantom.

Scholars believe colonial builders modified the traditional French practice by borrowing the use of Spanish moss from Native Americans and expertise from African slaves who practiced similar wattle-and-daub construction.  This cultural fusion produced a new earthen building tradition that was communicated to settlements up and down the Mississippi River. The bousillage tradition peaked in Louisiana in the cotton era and died out around World War II.

Although the Heritage Area includes several examples of bousillage construction, Frantom selected the Buard-Wells House, believed to date to the American Revolution, to discuss render preservation techniques performed last fall.  Quality Finish has worked to preserve and study the Buard-Wells House for twenty years with the help of Mrs. Thomas H. Wells, owner, archivist, and historian.  The team documented removal of loose material, a task made easier by the Creole tradition of numbering posts.  The friable bousillage render, was strengthened by applications of lime water and a mixture of clay, lime, and fiber, floated on in thin coats.  While curing, moist burlap pecan sacks were used to cover the walls and slow drying of the applied treatment.  Finally, acrylic-bound limewash was mixed using Edison 342 and Graymont Type S autoclave lime and applied in three coats.  While the render takes months to cure, it protects bousillage from the effects of weathering. When combined with design feature like roofs with broad, overhanging eaves, a rendered bousillage wall can last for many years.

Frantom’s presentation promotes awareness of the distinctive cultural traditions of northwestern Louisiana and was funded in part by an award from the Cane River National Heritage Area, Inc., and a grant from Adobe in Action, sponsors of the Earth USA conference.

Lean more about bousillage in this NCPTT video: The Historic Building Material Bousillage.

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