Example of damage from rust jacking
Crack along tabby pour line where parapet was not connected to the interior structure
By Bruce PIatek, JIA Director of Historic Resources
Ken Smith Architects and Fourth Street Design and Restoration did a wonderful job of restoration of the Hollybourne Cottage. This is one of the most iconic buildings in the National Historic Landmark District. The building was at risk of structural failure and partial collapse. The most at risk part of the structure was the parapets along the roof line. These poured tabby elements were never connected to the internal wooden structure of the building. Furthermore, the rusting of the steel lintels, or supports, over the window and door openings had caused rust jacking that broke the adhesive bond between the tabby courses. The result was that the parapets and sections of the exterior tabby walls were only held in place by gravity. In some places the rust jacking was so bad that one half to three quarter inch cracks existed under the parapets and daylight could be seen through these cracks. Hollybourne was literally falling apart.
Once I realized the scope of the problem, I called in Ken Smith, one of the only architects that have worked on large pour tabby buildings like Hollybourne. Ken had experience working on Henry Flagler buildings in St. Augustine that were built about the same time and with the same materials. Ken and Structural Engineer Jude Kostage developed the approach to support the tabby walls while the support lintels were removed and new support components were installed. Fourth Street Design and Restoration executed the plans which also included connecting exterior walls at the parapets to the interior wooden structure of the building. There work was outstanding and they showed a passion for doing a good job and getting it done right. There was risk involved in the work. A failure of a temporary support over a window or door opening could have brought down a section of the exterior wall.
The Jekyll Island Foundation’s generous donors helped to defray the cost of the architectural and engineering services that were the key element in the success of this important restoration project. Donor’s contributions helped to insure that Hollybourne Cottage will remain a spectacular architectural example and important historic asset in our National Historic Landmark District for years to come.