Land’s End Retaining Wall

In 1923, the City and County of San Francisco Department of Public Works built two retaining walls near Fort Miley in conjunction with the construction of El Camino Del Mar. The walls would have prevented the existing slope from encroaching onto the privately owned Market Street Railway right of way. Today, the right of way serves as the Coastal Trail at Land’s End in the Golden Gate National Recreation Area. The retaining walls are battered and curve with the surrounding terrain. The two walls are adjacent to the Coastal Trail and are 80 feet apart.

ARG Conservation Services was retained to provide specifications for paint removal and repair of the two retaining walls. The walls are made of cast reinforced concrete with rectangular and triangular protruding panels. The panels are covered with grey paint, beneath which are multiple instances of graffiti as well as earlier paint layers applied to obscure graffiti. Light soiling and lichen cover the walls. Additionally, minor repairs are needed where concrete exhibits cracking, spalling, efflores-cence and mechanical damage.

After performing on-site testing, ARG Conservation Services recommended the use of the Sponge-Jet® system for paint and graffiti removal. The 80 grit sponge media was recommended to remove multiple layers of paint, while the 120 grit sponge media was prescribed to remove dirt and lichen growth. Recommended repairs include filling cracks, spalls, and larger areas of loss with a custom patching mortar to match the walls’ original color and texture.