by Arthur L. Sanders
Repointing, repair, partial rebuilding, or replacement of brick masonry on a historic or landmark structure can be time-consuming, noisy, and dust-producing work, with scaffolding covering the building for some time. It can be tempting to look for a fast, easy solution. Once an investigation identifies problem conditions, Band-Aid repairs, such as application of water repellant coatings or sealants, might seem to take care of the problem.
If the building is mass wall construction designed for mortar, it’s best to stick with mortar. When moisture does find its way behind brick masonry, it can work its way out through mortar joints. Properly designed brick masonry walls get wet and dry out. If joints are sealed, the trapped water will further break down the masonry, while the sealer hides this ongoing deterioration.
Why do brick and mortar deteriorate? Some contributing factors architects look for include:
- Excess moisture penetration at joints.
- Weathering, including exposure to successive freeze-thaw cycles.
- Contemporary conditions, such as pollution.
- Uneven settlement of the building foundation.
- Thermal movement of masonry.
- Capillary action causing rising damp (water drawn into the building materials from the ground up).
Often, a combination of factors may be the culprit in masonry deterioration. The investigation phase of a historic or landmark brick rehabilitation project may be longer than with modern construction, but this extra time is essential to uncover the root cause of the deterioration. For a repair effort to achieve lasting success, the plan must address underlying conditions.
With historic or landmark structures, special considerations may arise during the investigation. To avoid change orders and delays caused by unforeseen conditions, the design professional may need to research original construction documents and records of earlier repairs and alterations. Onsite observations complement this evaluation, as portions of the original documents may be unavailable, and building construction can deviate from that shown on plans. Test cuts, probes, photographs, and laboratory analysis may be part of this investigation.
If the building is a National Historic Register property or significant landmark, relevant regulatory issues must be addressed as early as possible in the project. The process of gaining approval for construction can take time, so the design professional researches the necessary codes and regulations and initiates the process of obtaining required variances and endorsements during the initial investigatory phase.
Once historic commission and other regulations have been taken into account, probable causes have been considered, and drawings and other construction documents have been examined, a brick rehabilitation and maintenance program can be designed to meet the needs of a historic or landmark building.
Repair of the masonry may be a time-consuming and exacting process. Replacement mortar and brick must visually match the original yet be resilient enough for contemporary conditions. If done well, masonry rehabilitation can restore the structural and aesthetic character of a building. If done improperly, a repair project can not only detract from the building’s appearance, it can cause lasting harm to the masonry.
While brick rehabilitation on a historic or landmark structure can be disruptive, the investment in proper techniques and materials means longer-lasting solutions. Inexpertly conceived repairs diminish a historic building’s aesthetic character and can exacerbate deterioration. Though it may not be a quick fix, a thoroughly researched and exactingly executed remediation program can satisfy budget and design objectives, with minimal disruption to occupants and as efficient a schedule as possible.
Arthur L. Sanders, AIA is senior VP and director of architecture with Hoffmann Architects and an active member of the Construction Institute.