Pavement mosaics

Karen Fix <kfix [at] getty__edu> writes

>We are working on a project involving pavement mosaics (limestone)
>where the surface has roughened over time and resulted in a loss of
>color brilliance. The maintenance crew currently tosses a bucket of
>water over the surface to enhance the colors; this, of course, is
>adding to the normal deterioration mechanisms of the mosaic.  As an
>alternative solution, we are considering applying a coating with an
>appropriate refractive index, which would then conceivably smooth
>the surface enough to reduce the reflectance and allow the colors to
>appear darker.

The floor of the Pennsylvania tate capitol building in Harrisburg is
paved with over 4,000 square feet of earthenware tiles in mosaic
patterns designed and made by Henry Chapman Mercer in 1903.  As part
of the Capitol Restoration Committee's overall restoration of the
structure we examined, documented and sampled the floor, looking
into its maintenance history and intervening repairs.  Originally,
these slightly porous tiles were surface treated with linseed oil to
saturate the surface optically and to retard moisture penetration.
For the next period of decades the floor was waxed.  In more recent
decades the floor has been coated with acrylic polymer emulsions.
The current treatment involves careful stripping and recoating,
again with polymers, and the development of a well planned
maintenance cycle:  not too much, not too little.   While there are
a variety of problems with the tiles and their grouting, the
potential problem of lifting tiles from moisture build up that
Shelley Paine suggested is not one of them.  If you would like to
discuss this project in more detail please call.

Kory Berrett
Berrett Conservation Studio
610-932-2425

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                  Conservation DistList Instance 12:65
                 Distributed: Tuesday, February 9, 1999
                       Message Id: cdl-12-65-005
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