Richmond, Calif.-based Alten Construction has begun construction on the historical Napa County Courthouse in Napa, Calif. The $11.6-million project will repair the courthouse, which was damaged by the South Napa earthquake that hit August 24, 2014.

The courthouse suffered major structural damage to existing unreinforced masonry walls, plaster finishes, finish carpentry, HVAC, fire sprinkler and electrical systems.

Alten's 16,000-sq-ft rehabilitation work will include courthouse historical renovation, a structural retrofit and new restrooms.

“Our team truly enjoys the task of preserving historical elements and restoring significant buildings to their original glory,” said Bob Alten, president of Alten Construction in a news release. “For us, it’s about leaving a lasting legacy for the courthouse that honors its past but positions it for the future.”

The repairs also include deconstruction, hazardous mold and lead abatement, structural, mechanical, electrical, fire protection and interior finishes. The antique elements that are being salvaged for the courthouse include the masonry, doors, windows, millwork, casework and lighting fixtures.

For parts of the project, the construction company is tasked with strengthening the walls using a custom-designed, externally bonded composite system, which is relatively new to the construction industry.

"We are faced with the challenge of demolishing existing load bearing walls and rebuilding them. Removal of these walls, without proper shoring and temporary support, could cause the building to collapse," says James Mitchell, Alten senior project manager. "We have hired a licensed structural engineer to design an extensive shoring system that will allow Alten to perform all necessary demolition and new construction of reinforced masonry walls. This temporary shoring plan will ensure the building is safe during our work and will not collapse."

To help with historical aspects of the renovation, Alten is working with architect and architectural historian Nancy Goldenberg, Carey & Co. (a Treanor/HL Company).

"The project involves removal, salvage, storage and restoration of historical items inside the courthouse," says Bob Alten. "These items must be removed to make way for the structural demolition and build back. They will then be reinstalled in the same place over the new reinforced and retrofitted structure. These items include, original wood trim, moldings, doors, door frames, wainscot, railings, cabinetry, windows, light fixtures etc."

Alten told me his company is working with the architect to develop a detailed catalog of all historical items to be removed and put back. "It is important that all historical elements go back to the original place in the building that they came from," he says.     

Other members of the project team include Santa Rosa-based TLCD Architecture for architect of fire, life safety, accessibility; Santa Rosa-based ZFA Structural Engineers as structural engineer; and AECOM serving as mechanical engineer, electrical engineer and construction manager.

The 18,000-sq-ft courthouse structure consists of an 1878 historical building that has been unoccupied since the earthquake. An addition was later built and is still in service for the County Court. Located at 825 Brown St. in Napa, the project is scheduled for completion in fall 2018.