When planning exterior repair projects, project teams sometimes speak of 20-year repairs, 30-year repairs or even 50-year repairs. These are the anticipated life spans of the major repairs carried out, with the expectation that the repair work will withstand the elements of weather and material degradation for one or two generations. The reality is that with most historic buildings, it is idealistic at best and dangerous at worst to expect major repair projects to completely eliminate the need for ongoing periodic maintenance and repairs. In some cases, the ongoing repairs required between major repair campaigns can be quite extensive. There are many variables that contribute to the longevity of repairs, including the original materials and repair materials, construction details, quality of work, climate and time itself.
In our work surveying monumental historic buildings, Vertical Access has the opportunity to see building systems of varying ages and degrees of deterioration as well as many generations of repairs installed to address this deterioration. Sometimes our investigations are part of the discovery phase of a major repair project, intended to be one of those 20-year or 50-year repairs. Other times, our survey work is part of a public safety inspection, either city-mandated or as part of a building owner’s self-mandated schedule.
Case Study: Two Historic Stone Churches
Looking at two examples of historic churches in the Northeastern United States, one a brownstone church and the other constructed of marble, the role of time in planning repair projects becomes more clear.
Delamination of brownstone seen at the darker red ashlar units. These units are face-bedded and of a different chemical and granular composition than the other ashlar units.
Some brownstones, when used as a building stone, are notorious for their poor weathering characteristics. The laminar nature of the stone and physical composition of many types of brownstones make them susceptible to ongoing deterioration. Vertical Access recently surveyed the exterior masonry of a brownstone church after church officials noted some pieces of brownstone that had become loose. The last major repair project at the church was carried out in the early 1990s, about 20 years ago. Repairs to the exterior masonry included retooling the brownstone and installation of replacement units.
In its recent survey, VA found that the the replacement units were in very good condition and most areas of retooling were sound. However, those brownstone units that appeared to have a finer matrix and different clay content suffered from more widespread delamination and erosion. The deterioration noted at some units is due to their face-bedded orientation and at others to the large surface area of stone at some of the carved elements. From the hands-on survey that VA performed, it is clear that the 20-year mark is past the lifespan of the repairs that were carried out for some of the stonework of the exterior.
Removal of marble at ornamental unit during a periodic inspection for public safety.
In the case of the marble church, a major restoration was carried out over 30 years ago. Planning for the next major restoration began almost 10 years ago, with a full survey of the exterior masonry. Public safety inspections were performed periodically during the design phase of the exterior restoration. As with the brownstone church, the public safety inspections of the marble church identified material deterioration of concern. Finally in 2012, construction for the major restoration project has begun.
These two examples of historic masonry churches illustrate the role that time can play in planning a repair project. Often we have unrealistic expectations of how much time our repairs will last. This may lead to concerning or even hazardous conditions developing on our buildings before a plan is in place to address them. Ideally, periodic inspections made in the interim between major repair campaigns will improve both public safety and capital planning for the facility.