When pieces of stone began detaching from the historic Guardian Building (previously known as Brooks Building) and falling onto the sidewalk below, the situation quickly evolved into an urgent public safety concern. The building’s owner, who also happened to be an attorney, recognized the legal and safety implications immediately. Within hours of the initial call, our team mobilized and installed emergency scaffolding to protect pedestrians and stabilize the area.
What began as an emergency response soon expanded into a full-scale historic restoration, supported by a Historic Places grant that the owner secured after researching preservation funding. This grant opened the door to rehabilitating the building’s entire stone façade, an effort that required accuracy, craftsmanship, and creative problem-solving.
Re-Creating an Eight-Foot Parapet—Without the Original Stone
Among the most challenging elements was the parapet. Large sections, some up to eight feet tall, were missing entirely. To qualify for historic tax credits, every reconstructed component had to match the building’s original design as closely as possible.
However, one major obstacle stood in the way:
The original brownstone used on the building had come from quarries that were now permanently closed and located within protected national parkland.
Replacing the parapet with newly quarried stone was simply not an option.
Our team proposed an alternative solution; one that would maintain historical authenticity while meeting modern material and preservation constraints. Instead of traditional stone carving, we recommended using precast concrete designed to mimic the appearance and texture of the original historic brownstone.
Craftsmanship Meets Innovation: AAC Templates and Historic Carving Techniques
To bring this plan to life, we partnered with two specialized groups:
- Stoneworks Architectural Precast: A precast concrete supplier who would produce the final architectural pieces
- Architrave Stone: a carving company skilled in historically accurate stone replication
Our team provided Architrave with large blocks of autoclaved aerated concrete (AAC), a lightweight, easily carved material ideal for template creation. Using archival images, they meticulously carved AAC models that replicated the building’s original parapet elements.
One of the most important references was a photograph from around 1920, taken before the parapet had deteriorated. This single image, captured from across the street, became the visual blueprint for reconstructing the building’s historic profile.
Once the AAC models were complete, we delivered them to the precast supplier. There, molds were created based on the carvings, and the final concrete pieces were cast. These precast units were then installed around the entire perimeter of the roofline, seamlessly returning the Guardian Building’s silhouette to its original grandeur.
Sourcing Stone: A Journey from India to Lake Superior
During the exploration phase, the team evaluated multiple stone samples, each with its own story:
- A striking red stone from Arizona
- Another deep-hued sample sourced from India
- Genuine brownstone from the Apostle Islands in Lake Superior
- Several additional samples originating from Utah
The Apostle Islands sample was especially significant, as it represented the original source of brownstone historically used in many Midwestern buildings. However, since the region is now a protected national park, quarrying new material was prohibited.
At one point, a fascinating, but admittedly far-fetched, conversation even surfaced:
Legend has it that a ship carrying quarried brownstone once sank in Lake Superior.
There was brief speculation about whether salvaging that stone might be possible, but the idea remained little more than a story, an intriguing footnote in an already complex restoration project. As our team joked, it’s hard to know who you would even call to begin arranging a salvage operation for a century-old shipwreck filled with stone.
Rebuilding the Past While Protecting the Future
The Guardian Building restoration became much more than an emergency response. It represented a delicate balance between historical preservation, structural safety, and modern construction techniques.
From interpreting century-old photographs to recreating eight-foot architectural elements with modern materials, the project showcased what’s possible when history, craftsmanship, and engineering come together.
And in the end, the Guardian Building regained not only its iconic parapet but also a renewed sense of architectural identity; one that honors its past while ensuring its longevity for decades to come.
