Unique Materials, Approach Key to Success for St. Alphonsus Restoration
Balancing the vision of the original architecture with modern safety devices is a real challenge for a historic church. Such was the case for St. Alphonsus in Baltimore, Md., a 8,200 square foot church, originally built in 1845. The structure recently underwent a major renovation that included installation of 20 new architectural spires on top of the pilaster caps. Although these slender, pointed spires appear as ornamentation that complement the architectural vis`ion of the historic building, they also double as a lightning arrestor system to protect the building from a potentially dangerous strike during a lightning storm.
The church was originally designed by Robert Cary Long, a Baltimore-based architect who designed a handful of local churches before his early passing at the age of 39. The church was originally given the nickname of “the German cathedral” due to its Southern German, neo-Gothic style of architecture. For years, St. Alphonsus was an important part of the German community and served as the local headquarters for the Redemtorist Fathers and Brothers. In 1909, the spires, which were replaced as part of this renovation, were removed from the church. Since that time, the church was acquired by the Roman Catholic Lithuanian Parish of St. John the Baptist. Many other activities have marked the church’s history, but the most impressive is likely the fact that, pending the beatification of Father Francis X. Seelos, the church may become the only in the country to have once had two former pastors become canonized saints.
In order to improve the safety of the church, the owner, the Baltimore Archdiocese, sought an architectural feature that would match the original spires. New spires were to be added around the lower roof-top perimeter of the sanctuary in locations which had once contained the architectural features that the replacements were modeled after. Installation of spires on all of the piers climbing the steeple is planned when the budget allows for the addition.
With extensive experience on several projects for the Baltimore Archdiocese as well as unique expertise in historic preservation and restoration, Structural Preservation Systems, LLC (SPS) was hired to perform the renovation.
SPS also had prior experience at St. Alphonsus that involved injection of cracks in the pier caps as well as creating a mold to cast and carve new replacement pier caps where the spires are now being replaced.
Before the project even began, the project was met with key challenges. According to Christian L. Hill, SPS Project Engineer, one of SPS’ key responsibilities was working with the owner and the engineering team from Keast and Hood Company to find a way to fulfill the vision with a limited budget. Also, there was some concern about the durability and appeal of the spires, he said.
“The pieces needed to fit the original model and still be able to hold up to the current conditions in Baltimore City,” said Hill. “Because of the increase in pollution, volatile chemical usage and natural wear-and-tear, there was a major concern about the durability of the spires.”
To alleviate this concern, the team decided to brush-apply an additional coat of paint on top of the spray finish to ensure that any soiling of the project would occur at a slower rate. This solution also will enable the spires to be easily cleaned by a non-specialized maintenance staff.
SPS also was cognizant of the fact that the piers were not supported in a vertical fashion. Since the piers are slightly crooked, the spires may appear to be out-of-line when placed vertically into the holes. In response to this challenge, SPS suggested shimming the brick piers level, which allows for easy straightening if necessary. After discussions with the owner and an inspection of the first “mock-up” spire, this solution was not implemented. A thick base molding was placed around the spires in lieu of shimming the piers; adding visible bulk and making the spires appear to stand in a much prouder fashion.
The prior work performed by SPS served as the prep work needed to get the pier caps ready for the spire installation. Any cracks existing within the caps were filled with an injection grout and the broken or spalled caps were built up with a restoration mortar and carved back to their original shape. After the stones were restored back to their original condition, all of the caps were then covered with a stone stabilization compound. This stone coating is specially-formulated to penetrate into the substrate and hinder the infiltration of harmful exhaust chemicals into the porous material. It also clogs the pores and slows larger particles from being drawn through the stone by capillary action.
The installation of the spires began by drilling 41-inch deep and 1.5-inch diameter holes through the pier caps and into the brick piers. A number of drilling methods were evaluated. Ideally, SPS did not want to use typical hole boring equipment since most utilize water to lubricate the drive through the substrate. Water, if combined with the dust from the drilling, posed a serious problem as a cementitious slurry could result. Such a paste could slide down the pier, thereby staining the historic brick. As such, SPS used a waterless drilling mechanism. A special drill bit and extension rod was purchased to allow for dry drilling, which eliminated the problem. In the few areas where a wet boring was needed in order to not split a pier, a small containment reservoir was built on the cap and continuously vacuumed to control the slurry.
After the holes were drilled, SPS inserted a custom designed specialty anchor system into the hole. The anchor system is comprised of a steel section in a mesh fabric sleeve, into which a specially developed cementitious grout is injected under pressure. The flexible sleeve of woven polyester restrains the flow and expands to about twice its normal diameter, molding itself into the shape and spaces within the walls, providing a mechanical as well as chemical bond.
The anchors work by inserting a long (3.5-foot) piece of all-thread into the hole and then pumping grout around the anchor to hold the entire piece in place against the substrate. A 1-inch thick grout bed was then laid to bond the pier cap and receiver plate together. An 8-inch by 8-inch, stainless steel receiver plate was placed on top of the grout. Once everything had set and cured, the spires were attached to the plate by bolting the entire unit to the receiver plate. Then, the wiring for the lightning arrestor system was attached to the spire base and the actual lightning rod was screwed into the tip of the spire. The connection between these components was completed with a stainless steel rod running through the body of the spire.
The most important safety feature on this project dealt with the new slate and copper roof, which can become very slippery in the adverse wintry conditions. Since the roof of the church had recently been reconstructed, a tie-back line was placed around the entire roof perimeter. Throughout the entire construction process, every worker was tied to the roof, thereby increasing fall protection measures. Additionally, the public and surrounding property was kept safe by obtaining occupancy permits for all the parking meters and the parking lane on an adjoining street. As such, all passing vehicles or foot traffic could not interfere with the crew nor endanger themselves by keeping a reasonable distance away form the overhead work.
The total project time from delivery of the spires to completion was approximately one month. Drilling and setting of the anchors and grout took approximately two weeks to finish, followed by one week of miscellaneous painting and clean-up. Difficulties arising due to inclement weather during the winter season also cut approximately a week out of the construction schedule.
Material and Method Innovation
According to Hill, the most innovative idea incorporated into this project was the use of a highly unusual material for the spires. Historically, pieces are carved out of wood or molded from fiberglass. However, these spires were carved out of Polyvinyl Chloride plastic, commonly known as PVC. This solution not only reduced the cost of the manufactured products, but it also allowed for exceptional durability against the weather and pollution. While a simple fiberglass mold may not have allowed for such distinguished character within each member, these carved pieces were made individually by skilled craftsmen, similar to how the original ornaments would have been made. Each of the pieces were hand constructed with “routers and a bit of ingenuity” by the artisans.
The inclusion of the lightning arrestor system into the decorative pieces was another innovative technique. By using the spires for multiple purposes, St. Alphonsus Church was able to maintain the safety of their building as well as develop a decorative architectural feature which will enrich the building and surrounding community. Including the lightning arrestor system in the architectural pieces is a rather unique solution, and this is one of the first times that most all of the project members had been involved with a dual-use sculpture on a roof.
Mark Fitzgerald, the SPS foreman working on both the cap stabilization and spire installation projects, said that the innovation and execution of the project really makes a statement about the quality of the team working on all facets of the project. Others working on the installation with Fitzgerald include Deshaun Keller, Arasmo Santos, and Raul Ramirez.
According to Hill, many lessons were learned on this project that will prove useful in future historic renovation projects. By using the PVC material to construct the spires, Hill said they gained confidence about the use of plastics in place of other more traditional building materials.
Others lessons include the reminder that there is always a way to navigate through tough budget constraints when a team approach is used to finding the optimal solution.
“Especially in the historic field, there are new product and method ideas floating around that should be evaluated,” said Hill. “No method is set in stone, and there are many ways to complete a job with equal success for the owner.”
Doug Johnson, Project Manager from the Archdiocese of Baltimore agrees. “The effort of Jim Bohn (SPS Project Manager) and the entire team in figuring how to build and construct the spires was crucial. The design-build effort went above and beyond the services of a typical contractor. The use of new materials cut costs significantly and finished the project for a fraction of the cost of stone. From inception to completion, the SPS team brought a well planned and executed project to the table which resulted in [the spires causing] a big visual impact on the surrounding community.”
“The installed spires not only improve the appearance of the church, they also increase the safety of the building by providing a full lightning arrestor system,” said Deacon Hugh Mills, Jr. of St. Alphonsus Church. Deacon Mills continued by stating that the spires are, “the most beautiful project done to the church in many years. [The spires] restored an icon of the community which had been missing for nearly 100 years. All of the parishioners have taken notice and appreciate the work done.”