Repair and restoration of historical concrete and masonry structures requires methods and techniques that vary from traditional repair. Construction methods have improved, demolition requires extreme care, material compatibility is more than color matching, and protection of surrounding surfaces is critically important.
Incorporating improved construction methods without visual change to the historical architecture is critical to the restoration process and to governing authorities. Demolition methods require finesse to prevent micro-fractures and still provide the proper surface preparation to ensure lasting repairs. Material compatibility is more than an aesthetic concern. Incompatible materials can destroy the historic fabric. Also, the protection of surrounding surfaces is as important as the restoration itself.
The difference in repair materials is very significant. Jahn Mortars Restoration Systems provide materials that nearly match the existing concrete or masonry in color, expansion/contraction, and porosity. The use of aged lime putty has been an integral part of historical restoration in Europe and is now being used in the United States.
Concrete curbs were installed into the coquina stone walls at the Castillo De San Marcos National Monument in St. Augustine, FL approximately 60 years ago. These curbs expanded and contracted at a different rate than the coquina stone. The porosity of the two materials was completely different and moisture became trapped behind the concrete curb. The result was significant damage to the original coquina stone wall. We removed the concrete curb and laid new coquina stone to fill the void. Mortar for setting the stone was matched in color, porosity, and compressive strength to the coquina stone by Jahn. The new concrete slabs that have been installed do not touch the coquina walls.
Historic restoration at the Lightner Museum, the Castillo De San Marcos National Monument, Park Lane Hotel, and turn-of-the-century residences is rewarding. WE DO give each historic project the special attention required.