Mortar Joint Maintenance - From Abomination to Preservation

The tools outlined in this paper show how inadequate repairs impact masonry performance and how good quality repairs can reduce unnecessary expenditure and increase the service life of masonry buildings. This discussion focuses on identification of poor quality mortar joint repairs, understanding what constitutes proper and improper repairs, and the structural ramifications of poor maintenance. The authors have combined structural and architectural engineering experience drawing from evaluation and repair work on hundreds of projects to generate the field research for this paper. The maintenance of mortar joints in existing structures is critical to the long-term durability of the masonry wall system. Unfortunately, the maintenance of mortar joints is often overlooked until irreversible damage to the walls has occurred and serious structural concerns arise. The masonry degradation process has several stages, which if identified early can avoid more costly and extensive future repairs. Professionals may have limited preservation expertise to identify poor quality repair techniques during assessments that assist in generation of repair plans. Proving the value and performance of mortar repair is critical in validating the quality and cost of work. The intent of this paper is to disseminate compiled practical knowledge for the reader to understand and be able to identify less than desirable methods of mortar joint maintenance, understand why poor quality mortar joints do not perform over the long-term, and see the steps required to implement good quality, long-term, mortar joint repointing.