Project Focus: As consultants to Buell Kratzer Powell, Ltd., Noble Preservation has undertaken a masonry conservation study for severely deteriorated sandstone and is in the process of preparing specifications in anticipation of the building's restoration. For architects, dark sandstone like that used on the main facade construed a departure from the lighter shades of the Classical Revival; for masons, sandstones could easily be carved into ornate capitals and wall ornamentation. These desirable properties are due to the sedimentary nature of the stone and the fact that many contain abundant clays and iron oxides (which provide color and relatively loose intergranular bonding). In many respects, deterioration of the brown sandstone facade is consistent with what has been noted for similar urban sandstone buildings for more than a century. Just a few decades after sandstone became popular as a building material in the mid-19th century, significant variations in stone quality and improper construction practices combined with a temperate environment and contaminants associated with urbanization began to threaten the long-term stability of many such buildings. Some types of deterioration have as much to do with the nature of the material itself as they do with the manner in which the building was constructed. The particular varieties of sandstone used for the façade are poorly-cemented and contain significant quantities of clays; thus, they are highly susceptible to moisture-related deterioration such as delamination, cracking, detachment and disaggregation. Additionally, many elements were face-bedded, or aligned so that their natural bedding planes run parallel with vertical weathering surfaces; this method of construction exacerbates problems with moisture and renders such elements even more likely to deteriorate. Overall, the Blue Horizon's sandstone features range in condition from very good for wall veneer panels on the upper floors to unsalvageable for face-bedded window surrounds and sills on upper floors. At present, we are continuing laboratory research and are actively refining our conservation program in anticipation of construction beginning in 2000. |
 The Blue Horizon is characteristic of many late 19th century sandstone buildings in urban areas - affected by severe delamination and other problems.
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