The concrete exterior of Herrick Chapel at Occidental College had accumulated water damage over time, causing iron jacking on all levels of the building. Iron jacking is a condition in which water penetrates the concrete down to the iron reinforcement, causing rust (iron oxide), which takes up more space than just iron, inside the brittle concrete. This “jacks” the concrete, causing cracks, spalls and damage.
To repair the concrete and prevent spalling from reoccurring, Kaptive C&P opened the concrete and removed the rusted iron. We then replaced it with stainless steel, epoxy-coated rebar, or fiberglass rebar, before replacing the concrete in the affected area. We then applied a coat of Dunn Edwards elastomeric paint on the building’s exterior. Elastomeric paint is typically used in this process, because it bridges small cracks and creates a waterproof barrier. Its elastic properties also allow it to expand and contract with the substrate, preventing moisture penetration and extending the life of the structure.
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