Encaustic tiles

The entrance hall and vestibule of Parliament House in Melbourne,
Australia has a very elaborate and significant encaustic tile floor
made by Minton dating from 1879.  Accidents and the
over-enthusiastic use of floor polishing machines has abraded the
tiles.  While this practice has now been stopped, many tiles are
badly damaged.  In some cases only the fire-skin has been lost,
while in other areas have very deep losses. Where tiles have been so
badly abraded or cracked that they provide a tripping hazard, it is
proposed that they be replaced.  The original tiles appear to be low
fired, with fine coloured clay in the top and bottom surfaces, and a
coarser central section.  Reproduction tiles sent from UK
manufacturers appear to be slip cast, homogenous, more vitrified and
harder than the original tiles.  A ceramicist here in Melbourne has
made tiles apparently using the original materials and techniques
(including the coarse interior)--these look very similar to the
originals.

We will be undertaking research into the composition and mechanical
properties of the originals and all the proposed replacements, with
the aim of finding replacements with similar mechanical properties
and appearance to the originals.  There is concern that inserting
harder tiles into the original floor could be problematic, and we
were thinking we need to find replacements with similar wear
characteristics to the original tiles.  Is this necessary?

If so are there any suppliers of encaustic tiles made using
Victorian era techniques and firing temperatures?

We are also aware that inserting single tiles into an existing
mortar bed can be problematic given that lime mortar tiled floors
can behave as one unit and new materials may disrupt this.  We
intend to analyse the original mortar and replicate it--is this
sufficient or would there still be issues?  Some of the reproduction
tiles are thinner than the originals and so would need a thicker
mortar bed.  Would this be problematic?

We would be grateful for any comments on this issue.

Jenny Dickens
Senior Conservator
Heritage Victoria
GPO Box 500
East Melbourne  3002
Australia
Fax: +61 3 9637 9503


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                  Conservation DistList Instance 22:15
                Distributed: Monday, September 15, 2008
                       Message Id: cdl-22-15-014
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