Mission Beach Boardwalk, Seawall, and Lamppost Reconstruction
Location:Mission Beach, San Diego, CA
The Mission Beach Boardwalk is comprised of a 0.3-mile pedestrian-only thoroughfare. Construction of the Boardwalk began in 1925 and coincided with the development of the Mission Beach Amusement Center (now known as Belmont Park). The National Register eligible resource consists of a walkway, seawall, seven open balustrade walls, and 26 light standards.
Over the past 91 years, the Boardwalk has underdone many repairs. As early as the 1950s, the seawall had already received its first of many concrete parge coats as an attempt to conceal spalling concrete and exposed rebar. As suspected, the condition only worsened, eventually voiding the resource of ornamentation. Most of the balustrade openings were infilled and in some areas the parge coat on the seawall increased the overall thickness of the wall by 1/2” – 1”. The most disconcerting condition issue was one that could not be seen. The sand under the boardwalk had been undermined, causing large voids under the paved surface susceptible to collapse. As a temporary fix to conceal the cracking, asphalt was placed over the historic pink-colored concrete. Lastly, research revealed the 26 light standards were actually the fourth generation lampposts and did not remotely resemble the historic light standards. When IS Architecture was contracted to provide historic preservation construction observation services, the resource was a far cry from what it once was.
Challenges and Solutions
Once construction began, our firm was retained to provide historic construction monitoring services. It did not take long to realize the proposed drawings did not reflect the historic detailing of the wall, but they reflected the existing appearance of the wall with its many layers of concrete parge. In addition, the concrete specifications for the boardwalk did not include a pink-colored concrete which had become lost under multiple layers of asphalt. Although the proposed design was done with good intentions, the late involvement of historic assistance coupled with concealed historic details provided many challenges to this project.
The first step was to have the contractor saw cut a section of the wall to reveal the historic profile. From this physical section together with almost illegible as-built drawings of the seawall from 1925, we recorded the necessary measurements and drew a revised wall detail. The first few months of construction involved revising the drawings to reflect the historic design.
As research commenced, a historic newspaper article revealed the original model of the light standards; Edgewater. A quick search on the internet revealed Spring City Electrical of Spring City, PA manufacturers the Edgewater series and is hence, what was ordered for this reconstruction project.
Constructability proved to be the next hurdle. The required amount of rebar and strength of the concrete together with the intricate design of the open balustrade wall proved to be the most challenging from a constructability stand point. Numerous mock-up walls were fabricated to perfect the method of construction and to assure the design requirements from a structural and historic perspective were achievable.
Secretary of the Interior’s Standards
The City of San Diego Historic Preservation Ordinance requires any building or structure over 45 years of age to be evaluated for eligibility on the Local Register listing. The Mission Beach Boardwalk, completed in 1926, meets the age criteria and upon further review was determined by City Historic Staff to be eligible for the National Register under Criterion A as a significant contribution to San Diego’s history, under Criterion B for its association with historically significant individuals, and under Criterion C for the period and method of construction.
Due to the boardwalk’s irreversible state of deterioration, reconstruction was the approved treatment approach recognized by the Secretary of the Interior’s Standards for Historic Properties. The boardwalk, seawall, open balustrade walls, and light standards were fully reconstructed in 2015-2016 to its 1925 original design.