A five-story, 32-unit affordable apartment building is expected to begin rising on Shoreline Highway in Tam Valley as early as Monday, Aug. 31, pending permit clearance. The modular construction phase will bring two weeks of truck traffic, parking restrictions and construction noise to the Shoreline Highway corridor near the northbound Highway 101 exit.
The developer, The Pacific Companies, moved a large crane onto the site at 156 Shoreline Highway on the morning of Aug. 25, according to a Marin County news release. Underground work is complete. But the start date remains conditional: the county said modular installation will begin only after "outstanding permitting requirements" are resolved, and the installation schedule "remains subject to change." The county had previously issued a stop work order after construction proceeded while building permits were still being finalized.
What drivers and neighbors should expect
Once work begins, prefabricated modular sections will arrive by truck every 30 to 60 minutes during weekdays. A crane will lift and secure each section into place. The county said most traffic holds will last 60 to 90 seconds, though some may run longer. Up to four large transport trucks may be staged along Shoreline Highway at a time, and traffic control measures are planned near the northbound Highway 101 exit.
Temporary parking restrictions will be in effect along the affected stretch of Shoreline Highway from 6 a.m. to 7 p.m. daily. Overnight parking will remain available. No weekend work is anticipated.
The installation phase is expected to last up to two weeks, depending on weather, transportation and other logistics. Caltrans has been notified and the developer holds Caltrans permits for the work.
Project background
The Marin County Planning Commission authorized the project on May 29, 2025, under SB35, a 2017 state law that lets qualifying affordable housing developments bypass standard environmental review and limits the county's ability to reject them. The application was submitted Nov. 27, 2024.
The 32,378-square-foot building will sit near the Manzanita park-and-ride lot and the Highway 101 overpass at Richardson Bay. Units will range from 544-square-foot one-bedrooms to 751-square-foot two-bedrooms.
The Shoreline Highway project grew out of a larger affordable housing proposal at 825 Drake Avenue in Marin City. That project, originally approved for 74 units, was split after years of opposition and legal challenges, according to SFGate. The Marin County Board of Supervisors brokered a compromise: 42 units at Drake Avenue and 32 at the Tam Valley site. Modular installation at the Drake Avenue site began in January 2026.
Construction updates
The county said it will post weekly updates on its project webpage. Questions about construction activity can be directed to Immanuel Bereket, a principal planner with the county's Community Development Agency, or to the developer through its website.
