A project of the Research into Practice Initiative

May 24-28, 2010
New Orleans, Louisiana

salt deposits on masonry

From Angkor to Zanzibar and Venice to New Orleans, soluble salts are responsible for causing significant damage to porous building materials. But how does salt weathering take place, and what level of salts are harmful? Are certain salts more damaging than others? Should they be removed and if so, how?

The use of poultice treatments for desalination is well established in conservation, however the complexities of salt migration within historic structures have produced variable and unpredictable results. Poultice Desalination of Porous Building Materials presents new applied research on the process of poultice desalination through practical applications for conservators and others whose job is to assess, treat, and evaluate the impact of salts on porous building materials.

Madame John's Legacy, New Orleans

Designed for field-based conservation professionals, this hands-on workshop was conducted through a combination of pre-workshop reading assignments and workshop lectures, demonstrations, and field trials—the latter of which were held at Madame John's Legacy in the historic French Quarter. It provided participants with a solid foundation for the poultice treatment of salt-laden building materials.

Topics addressed included:

  • Guidelines for poultice desalination
  • Building pathology and the larger construction context as it pertains to moisture ingress and egress and salt related damage
  • The kinetics of water
  • A review of the behavior of porous building materials
  • Salt and moisture transport through porous building materials
  • Introduction to salts and salt weathering
  • Working principles of poultice systems: optimizing salt removal
  • Criteria for poultice selection: modifying your poultice to match your substrate
  • Practical pre- and post- poultice treatment investigation and assessment methods
  • The limits of poultice desalination

The Poultice Desalination of Porous Building Materials workshop was organized by the GCI Education Department in partnership with the Louisiana State Museum and was a result of research conducted through the GCI Science project, Desalination of Porous Building Materials. It was the first activity of the GCI's Research into Practice Initiative, which aims to disseminate the results of important research to the conservation field.

Workshop curriculum (1page., PDF, 94KB)

Workshop bibliography (9pp., PDF, 381KB)

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Page updated: September 2010