In
June 2002 after an extensive structural analysis, as well as design and
installation of a structural retrofit to the floor above, remedial treatment to the detached areas
of the ceiling was begun. Since it had
been determined early in the assessment phase that treatment would not be
required on the entire ceiling, the first phase of intervention involved
identifying those locations where treatments were necessary. A final
determination was not made until after a comprehensive interpretation of the condition
of the ceiling using the results of the 1991 survey, the 2001-02 GIS analysis,
an assessment of the 1978 treatment, and mechanical testing of the preferred
adhesive formulations.
As
part of the 2002-03 conservation program for the Great Hall ceiling at Drayton
Hall, adhesive formulations developed by Morgan Phillips in the 1970s-80s were
tested and used for plaster reattachment.
The preference for an injection adhesive system was based on its
specificity of installation (i.e., localized, minimum treatment) and low-impact
on the historic fabric. This was all the
more critical as earlier stabilization of the ceiling, following the practices
of the day, limited access to the upper side of the lath and plaster, making
retreatment difficult. Mechanical
testing for tensile strength and, to a lesser extent, creep was performed on
Phillips’ formulations. In addition to
providing comparative data on tensile strength, creep, and modulus of
elasticity, the tests revealed the unintended effects of the fillers and
thickeners to mechanical strength.
|
