Floor finish

Deliberations are currently being made for specifications that will
impact the longevity and appearance of a newly installed parquetry
floor in a historic landmark.

The building: The Library of Parliament in Ottawa, Canada, underwent
a major renovation following a fire in 1952.  The original circular
Reading Room floor had a patterned geometric design using oak,
cherry and walnut woods.  The replacement 50's floor emulated the
original patterns and woods.  It was originally finished with an
unknown coating. The story:  As the finishes and wood were damaged
over the years (especially with [high] heels) the wood was reduced
with sanders through a number of campaigns to an extent that exposed
the tongue and groove joins thus rendering the floor functionally
irreparable.

The reflection:  Polyurethanes are a remarkable coating system in
many applications where durability is required. However, their
aesthetic properties are utilitarian and they do not provide the
appearance of an oil based floor finish that is characteristic of
19th century floors.  As well, a 50 year life expectancy for a
hardwood floor in a historical building is at best disappointing.
The difficulty with polyurethanes is that they are adhesive systems,
applied in multiple and discrete layers that do not lend themselves
to visual amalgamation in the event of localized repairs or
recoating.  The treatment indication is to remove the coating before
reapplication  and the tendency is to remove a portion of the
substrate along with the coating, usually with heavy sanding
machinery. The question:  Consideration is being given to the
application of an oil-based floor finish, specifically tung oil
modified with phenolic resin, to enhance the chatoyance and colour
of the wood, to emulate a more historically accurate overall
appearance, and to provide a surface that is renewable without
having to remove substrate material.

Has anyone had experience in the application and longer term
maintenance of an oil-based floor finishes?  Any thoughts for or
against?

Laszlo Cser
Restorart
Toronto, Canada


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                  Conservation DistList Instance 13:55
                    Distributed: Friday, May 5, 2000
                       Message Id: cdl-13-55-009
                                  ***