Guidelines for Cemetery Conservation - National Trust of Australia

GUIDELINES FOR CEMETERY CONSERVATION
PART THREE - HOW
2.2 Monuments
2.2.1 Introduction
A guide to the conservation of monuments, and notes on the physical preservation of
gravestones are included in Part 4, Appendix 5. It should be noted that the actions suggested
can only be guidelines and may not be always applicable.
The National Trust recommends that expert advice be sought in any case where the most
appropriate form of treatment is not clear. A list of professionals with conservation skills is
available from the National Trust and the Heritage Branch of NSW Department of Planning.
The National Trust’s Cemeteries Committee is available to comment on particular cases or
proposals.
2.2.2 Deterioration of monumental stone
In planning conservation for a monument, it is useful to know the deterioration characteristics
of the stone types generally used in NSW.
Granite
Most granites are almost immune to weathering. Some may gradually lose their polish. They
will not generally be physically damaged by re-polishing, but:
• It must be realised that a re-polished stone is no longer “the original”.
• Loss of polish may indicate that the stone was poorly selected, and that cracks are
actually developing within and between the constituent grains. In this case, physically
handling the stone may cause serious damage.
• In the case of “black granite”, loss of polish may be caused by solutions washed out
of unsuitable jointing (especially Portland cement) above the polished surface.
Replacement of such jointing with an inert filler is more important than re-polishing
of the stone.
Marble
Because marble always gradually dissolves over time, the incised inscription is typically
filled with lead or a metal alloy, to preserve the sharpness of the writing. In time, however,
the marble dissolves away from this lettering and the letters peel away from the stone.
This natural destruction is inevitable, but the process can be slowed to a great degree by
appropriate management.
The situations which lead to rapid erosion of marble are:
(a)
(b)
exposure to exhaust fumes from cars and smoke from coal fires;
growth of black moulds on the stone surface or green moulds just inside the stone;
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