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Subject: Survey on conservation of porous calcareous stone

Survey on conservation of porous calcareous stone

From: John Griswold <gcajg>
Date: Wednesday, October 28, 1998
    **** Moderator's comments: Please respond directly to the

I am a conservator working as a consultant to a project on the
preservation of porous calcareous stone at the Getty Conservation
Institute.  I am collecting information pertaining primarily to the
conservation of limestone, but also related to marble and other
calcareous stone.  We are particularly interested in salt-related or
clay-related deterioration problems and solutions.  The information
collected will be synthesized and used in a report to the Scientific
Department at the Getty Conservation Institute to help guide current
and future scientific research.

The report will help focus the course of investigation by
establishing the resources, methods etc. that are currently being
used by conservators, conservation scientists and others to
characterize limestone, and determine mechanisms of deterioration
and rates of decay.  Of particular interest is the identification of
the common rules of thumb or indicators used to determine an
appropriate course of treatment.

This report supplements a comprehensive review of the published
literature on these subjects now underway; it is our intention that
the final version will be made available as an annotated
bibliography and review of current practice. Contributors will be
acknowledged in the report, but your name will not be associated
with any specific information you provide.  This review will also be
posted on the GCI's web site.

Attached are some questions that may provide an indication of the
range of information in which we are interested.  I welcome your
response to any or all of the questions.

Thank you for taking the time to respond to this query.  Please
contact me to discuss any questions you might have.

    What are the primary published sources of reference information
    that you use to guide your investigations?

    Do you use field tests to evaluate the soundness of stone, or to
    identify deterioration patterns or causes, or are samples
    returned to your studio or laboratory for evaluation?  What
    field or laboratory tests do you use?

    How often do you work with a conservation scientist, materials
    scientist, or engineer on a given stone conservation project?

    Briefly list, in general,  your methods for diagnosing problems
    and prescribing solutions.

    Briefly describe the types of consolidation treatments you have

    Have you identified clays as a primary or secondary reason for
    observed deterioration modes on artifacts or architectural

    In the instance of suspected salt crystallization damage, have
    you analyzed the salts, and used that information to design a
    course of treatment?  Please describe.

    Have you used data from mercury intrusion porosimetry tests or
    similar methods to determine the suitability of a particular
    treatment on a particular stone?

    What mineralogical information do you find most useful in
    characterizing modes of deterioration?

    How often do you rely on consultations with colleagues, either
    within or outside of your organization?

    How often do you rely on published literature?  Case studies vs.
    lab studies?

    Do you find the morphology of salt efflorescence a useful
    indicator for the condition of the stone?

    Do you have any treatment reports, condition reports, lab
    reports, etc. that you would be willing to share pertaining to
    the conservation of deteriorated porous calcareous stone?  Of
    particular value would be descriptions of both successful and
    unsuccessful treatments and evaluations of treatments performed
    in past years.  The identification of unsuitable treatments is
    particularly important in preventing the future loss or damage
    to historic patrimony.

    How do you determine, in the short term and the long term, the
    success of a consolidation treatment?

    Have you performed desalination treatments and, if so, do you
    generally use surface washing, immersion, or poulticing
    procedures?  Please describe.

    Do you monitor the desalination process and, if so, how?

    Have you used a preconsolidant before desalination of
    deteriorated stone?

    Do you rely on a commercial lab or supplier to analyze samples
    and recommend a product for treatment?  Comments?

John Griswold
Griswold Conservation Associates, LLC.
2054 Coldwater Canyon Drive
Beverly Hills, CA 90210
Fax: 310-271-5277

                  Conservation DistList Instance 12:40
                 Distributed: Monday, November 2, 1998
                       Message Id: cdl-12-40-018
Received on Wednesday, 28 October, 1998

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