This guide provides information on methods that can assist the design and conservation professional in the selection and use of consolidants for stone.

Use of a consolidant should be considered only after developing a thorough understanding of all factors contributing to the deterioration of the stone. Such an understanding is best reached through a comprehensive survey of existing conditions, environment, and a definition of stone performance requirements, followed by laboratory analysis of the stone and its deterioration products. With this information it should be possible to identify the decay mechanisms and to develop a conservation plan for the stone. However, careful preliminary investigation may indicate that consolidation is an inappropriate treatment.

Decay Mechanisms—A discussion of decay mechanisms is beyond the scope of this document; however, an understanding of decay mechanisms is critical to the evaluation and selection of appropriate treatment methods for stone including chemical consolidation. (See Bibliography for references.)

Stone consolidation should only be done as part of an overall conservation plan. Consolidating stone without resolving underlying problems contributing to its deterioration (such as rising damp or improper drainage) can cause the consolidation treatment to fail completely or to accelerate the rate of deterioration of the stone. The condition of the stone should be documented before and after treatment.

Past experience has shown that application of some consolidants may contribute to deterioration or create unanticipated problems. In some cases, it may not be appropriate to use a stone consolidant at all. Consolidation should be considered only after unsuccessful attempts to remove or modify degradation sources have been carried out.

Consideration should be given to the fact that consolidation of porous stone is an irreversible process. Consolidants that allow future retreatment should be selected if possible. For example, treatment of stone, particularly porous stone, with hydrophobic materials may not allow future retreatment with water-based consolidants.

No consolidant should be used that prevents or significantly retards water vapor migration through the stone.

1.1 This guide covers procedures for the selection and use of consolidants for preservation of stone.

1.2 When considering the use of stone consolidants, guidance from specialists experienced in stone conservation should be sought. Where work on features of artistic, architectural, cultural or historical importance is being considered, guidance from specialists in these fields should be sought. Historic preservation guidelines should be considered in planning the work.

1.3 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This guide is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects.

1.4 Limited description of tests are provided for informational purposes only. See the referenced standard for complete description.

1.5 The values stated in inch-pound unites are to be regarded as standard. The values given in parentheses are provided for information only and are not considered standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user to consult appropriate safety and health practices and determine the applicability of regulatory limitation prior to use.