Point Arena Lighthouse, owned and operated by the nonprofit Point Arena Lighthouse Keepers Inc., is located in Mendocino County along the Pacific Coast northwest of San Francisco -— and within 10 miles of the San Andreas Fault. The original lighthouse was erected in 1870 with brick- and mortar-type construction that was common to the era.
In 1906, a devastating earthquake that destroyed much of San Francisco also severely damaged the lighthouse station. The tower and residence needed to be rebuilt. A company that normally built factory smokestacks was commissioned to rebuild the tower to withstand earthquakes, which led to the first reinforced concrete design for lighthouses.
By 2005, almost a century of exposure to the harsh marine environment had taken its toll on the concrete tower. Sections of concrete were falling, as well as the corbel supporting the balcony, putting the public at risk. There was also marked deterioration around the tower windows. The balcony was eventually closed to the public.
After the project engineer removed the existing coating and identified repair areas, repair contractor Alpha Restoration & Waterproofing of South San Francisco removed the deteriorated concrete, cleaned and coated the steel with an epoxy-modified cementitious anti-corrosion coating, and replaced steel reinforcement as needed. For larger areas, the contractor installed cathodic protection anodes and then filled all repair areas with two-component, fast-setting, polymer-modified, cement-based mortar. In addition, crews applied both a three-component, epoxy-modified, cementitious structural resurfacing compound and an elastomeric, crack-bridging, anti-carbonation acrylic protective coating to the exterior of the entire structure.
The restoration earned a 2012 ICRI Award of Merit in the Historic Category. To read more about the International Concrete Repair Institute’s annual Project Awards and winners, visit www.icri.org.
Point Arena Lighthouse Restoration
Point Arena Lighthouse Keepers Inc.
Point Arena, Calif.
Alpha Restoration & Waterproofing
South San Francisco, Calif.
Menlo Park, Calif.