Making Seamless Repairs to Terra Cotta, Part 2: Remove and Repair
In Part 1 of this series, I discussed ways to restore damaged terra cotta without removing the unit. Here, I explore how to proceed when terra cotta is too damaged to remain in situ during repair.
Even extreme damage can be removed and repaired rather than replaced.
Sometimes, a terra cotta panel is just too damaged to repair without removing the unit. In these situations, many contractors choose to replace it with a cast replica. But that takes time, which slows the project down and costs money. A commercially cast panel could be a poor color match to the other units. It could also weigh more than the original unit, placing the structure at risk.
Cathedral Stone Products makes it possible to avoid all those issues. Our proprietary one-inch Air Hammer allows for detail work. Our standard and custom pigments ensure an accurate color match. And our Terra Cotta Coating Glaze helps restoration professionals achieve a generational repair that introduces no new problems.
A recent project in lower Manhattan is a typical example of our system’s effectiveness. The building’s terra cotta units were severely cracked. Replacing the units with a cast stone replica was the first solution the contractor considered. Fortunately, he contacted us before starting that expensive and time-consuming process.
Once repaired, these units were sounded, inspected, and ready to be reinstalled.
The contractor was surprised to learn that he could get a durable and authentic result by temporarily removing the units and repairing them on site using Jahn M80 Anchor Setting Mortar and M100 Terra Cotta Repair.
A durable and authentic result.
After his team returned from our required JAHN Certification in Masonry Restoration Workshop, the contractor built an area on top of the site’s sidewalk bridge where they could carefully fix each unit. They reconnected broken pieces with small stainless-steel threaded rods then embedded the rods in Jahn M80 Anchor Setting Mortar to ensure the pins would be properly secured.
In some cases, they used stainless-steel wire mesh as a means of maintaining the terra cotta’s characteristic hollow form and provide a sound surface to patch on. That mesh was covered by a thick application of M100 Terra Cotta Repair Mortar. Once repaired, these units were sounded, inspected, and ready to be reinstalled.
Our products are useful in this application due to three main factors:
Structural integrity. Restoring and replacing the original units puts no additional stress on the surrounding structure because these units weigh about the same going up as they did coming down—while also being fortified with rods and mesh for strength.
Performance. Formulated specifically for historic preservation, our coatings achieve a generational repair that replicates the purpose of the original glaze, which is to repel water and allow necessary vapor to escape.
Appearance. Using our pneumatic air hammer preserves the fine detail characteristic of terra cotta. Our Terra Cotta Coating Glaze replicates the color and sheen of the original terra cotta.
The finished units matched perfectly—because they were the original units, fortified and beautified. The contractor and owner had no worry that they would be too heavy for the surrounding structure, as a commercially cast stone piece could have been. And the color match was perfect, thanks to our laboratory-engineered color matching.
Note: Cathedral Stone Products can help you decide whether to repair in place, remove and repair, or replace with a cast piece, which can be the best option for extreme damage of some materials. See “Cast Your Own Panels to Save Time and Money” for more information on how to cast on site.
