Large-scale treatment approaches to the cleaning and repair of marble: The Metropolitan Club, New York City

Frank G. Matero and Alberto A. Tagle

Abstract

From 1987-1989 a comprehensive study of the exterior crystalline limestone and marble of the Metropolitan Club was undertaken in preparation for the restoration of the deteriorated landmark structure. Following the recommendations of that study, exterior masonry conservation work including cleaning, structural repairs, and consolidation began in 1989 and was completed in 1991.

Designed by the well-known New York firm of McKim, Mead and White, the Metropolitan Club was the most lavish and expensive club building of its day. Completed in 1894 at a cost of nearly two million dollars, the building was immediately heralded by the noted architectural critic and historian, Montgomery Schuyler, as “the largest, most imposing, and most luxurious of the clubhouses of New York”. This pronouncement was largely due to the use of costly marbles and related stones for the interior and especially the exterior. For the building’s exterior, White employed a highly pure, fine, white calcitic marble from Vermont for the walls and a coarse-grained, buff, crystalline dolomitic limestone or meta marble from Tuckahoe, New York for the trim work, balconies, cornice, and basement story.

By 1900, only sixteen years after its completion, unsightly discoloration of the Tuckahoe stone was already reported and by 1931, the discoloration was so severe that the club’s architects advised cleaning. Such recommendations went unheeded until 1965 when the building exterior was painted.

The poor appearance and historical significance of the exterior marble prompted consideration of the cleaning and overall conservation of the building’s exterior in 1987. Following petrographic analysis of the exterior stone, identification of the staining and soiling, and survey of the structural conditions, a full scale conservation program was developed using conservators and contractors to carry out the varied aspects of the work. Treatments included the removal of aged organic resin and cementitious paints and gypsum-carbon crusts, the removal of intrinsic iron staining using ammonium citrate poultices, the use of epoxy adhesive repairs and mortar fills, and repainting. Because of the widespread use of Tuckahoe limestone during the nineteenth century and its inherent tendency toward discoloration due to ferruginous accessory minerals, further research was conducted on the use of chelating systems for large scale removal of metallic stains from light colored stones.