Two-year project to rehabilitate roof aims to address skylight replacement next

The two-year construction project to rehabilitate the his­toric Marin County Civic Cen­ter roof is nearly three-quarters complete as crews have begun applying the iconic “Marin Blue” color on the Hall of Jus­tice (HOJ) wing. Weather per­mitting, the intensive project is expected to be completed by early spring 2020.

The rehabilitation work on the southern wing and li­brary dome was completed in March, now proudly sporting the finished Marin Blue color. Since then, the project has been focused on removing the old roofing material from the HOJ wing, which is the northern half of the building. The removal process is intensive, requiring a variety of methods ranging from pressure washing to ham­mer and chisel. The contractor is approximately 70 percent complete with the removal of the old material.

An eight-foot high expanse of white fabric along the north­ern wing is in place as a protec­tive enclosure for public safe­ty. It is designed to stop debris, work dust and other particu­late materials from leaving the construction area.

Application of the new poly­urethane membrane roofing material is now underway on the sections of the HOJ roof that have been cleared. The ap­plication of the final blue coat has begun on the northern wing and is approximately 30 per­cent completed. Concurrently, the gold metal ornamentation and detailing work will be con­ducted along the entirety of HOJ wing.

Once the Department of Public Works has completed the roof replacement project, work will tentatively begin on refurbishing the building’s skylights. The design process is underway and various im­plementation options are be­ing considered. The intention is to construct a skylight sys­tem that matches the original design plans by Frank Lloyd Wright, the legendary archi­tect who crafted the historic building, while taking precau­tions against impacts from the elements, such as leaking and warping. The skylights project will be handled separately from the main roof work and is ex­pected to begin construction in summer 2020.

The new roofing system will be durable, resistant to fire and high winds, easy to maintain and includes a comprehensive 20-year warranty. The mem­brane material is expected to increase the safety and lon­gevity of the iconic building. Through extensive testing, the membrane has shown signifi­cant color stability and should maintain the historic build­ing’s look for years to come.

The 470,168-square-foot Civic Center is the largest com­pleted public project that Frank Lloyd Wright designed and is listed in the National Register of Historic Places. The Civic Center is characterized by a concrete roof with distinctive blue coating and stylized orna­mentation. Dating to the origi­nal construction more than 55 years ago, the roof has had four layers of recoating and patch­work over the decades. Despite several repair projects, the old membrane was beginning to fracture and peel, resulting in leaks and color fading.

In 2015, DPW sought the expertise of independent archi­tectural specialists at Wiss Jan­ney Elstner Associates, Inc., to assess the roof. The com­pany determined that repairs were no longer a solution and the 220,000-square-foot roof needed to be replaced to pre­serve the historic building.

Once complete, the new roof will be one of the largest construction projects on the Civic Center since it was built in the 1960s. Not accounting for inflation, the Civic Center’s Administration Wing and Hall of Justice originally cost ap­proximately $14.6 million to construct.

In September 2017, the Marin County Board of Super­visors awarded a $17,842,799 contract to Arntz Builders, Inc., a Novato-based company, to direct the project. Rainbow Waterproofing and Restora­tion Company, which special­izes in historically significant landmarks, is handling the re­moval of the old roof and the construction of the new one.

The project is being funded by the Capital Improvements Fund. The County’s Depart­ment of Finance raised the nec­essary money by refinancing Certificates of Participation, which essentially are bonds for municipal and government agencies, in 2015 when market conditions were favorable.

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