1 INTRODUCTION

The Brooklyn Historical Society is a nationally renowned urban history center dedicated to the exploration and preservation of documents, artwork, and artifacts representative of Brooklyn's diverse cultures. It contains a premier collection of research materials, including a wide variety of written materials, graphic images, and recordings of oral histories. The society's headquarters in Brooklyn Heights, New York, is an ornate brick and terracotta building designed by George B. Post, a prominent architect of his era. Completed in 1881 (Willensky and White 1988, 589) (fig. 1), the building represents an early use of architectural terracotta in New York and, as such, has a particularly high level of architectural significance. The terracotta was manufactured by the Perth Amboy Terra Cotta Company (Matero and Bede 1992). Given the visual similarities between the brick and terracotta and that the firm began as a brick manufacturing company, it is likely that it produced the brick for the building as well.

As part of a larger campaign to rehabilitate the entire building, the historical society retained a series of consultants to develop and execute a testing program for cleaning and repointing the building.1 This article describes the testing program used to select materials and procedures for cleaning the exterior brick.

Fig. 1.

Brooklyn Historical Society's headquarters in downtown Brooklyn, New York