The Mission museum is the original 1809 adobe Convento, the former Padres’ living quarters. It is the oldest standing building in Alameda county. Its importance is recognized by the National Register of Historic Places and the California State Historic Landmarks Commission. Unfortunately, a portion of the building’s foundation is badly in need of repair work.
The building was constructed using typical mission-era practices. The walls are made of Adobe clay bricks and support roof trusses made of redwood. The building is the only surviving part of the original mission complex, most of which was destroyed in an 1868 earthquake. (The adjoining Mission church was completed in 1985 and is a replica of the 1809 church. Click here to read more about the history of Mission San Jose.)
When cracks above the rock retaining wall on the Mission Blvd side of the museum began to appear the parish had a team of experts investigate in 2021. They discovered that, for reasons unknown, this part of the building was constructed on un-compacted native soil instead of a typical stone and compacted soil foundation. And the rock retaining wall in front of the building does not extend under the adobe wall and is starting to fall apart. Unless the missing foundation support for the adobe wall is created and the rock retaining wall replaced, this portion of the building could collapse in an earthquake.
Our engineering and geotechnical experts have created a plan to reinforce the foundation under this portion of the adobe wall. The existing rock retaining wall will be temporarily removed and the soil below the adobe brick wall will be injected with soil cement grout to fill existing voids and improve the strength of the subgrade soils. The subgrade soil will be jet-grouted to a depth of 8 feet below the base of the adobe brick wall and 2 feet laterally behind the face of the adobe brick wall. Temporary excavations are needed to provide access for the jet grouting drilling equipment. To prevent damage to the adobe wall, excavation will occur in six-foot sections, one section at a time. Following grouting of the subgrade, a new concrete retaining wall will be constructed in place of the existing rock retaining wall. The new retaining wall will be faced with some of the removed retaining wall rock to conceal the concrete structure.
We have submitted our repair plan to the City of Fremont for permitting, and a signed construction contract is in place. We are ready to proceed with this essential repair project during summer 2023. As part of the Mission’s 225th anniversary activities, the parish has raised $100,000 towards the $600,000 cost of the project. We have also received a $100,000 grant from the Committee for the Restoration of Mission San Jose, a $25,000 grant from Alameda County, a grant from the California Missions Foundation, and donations from generous individuals.
Help us preserve our 1809 Museum & Gift Shop for future generations
Click HERE to become part of our history with a donation to this project and to see a list of our donors.