Jemcor Proposes 441 Unit Residential Complex at San Mateo Office Site

Developer Jemcor Development Partners files plans to demolish a San Mateo office building for 441 housing units, leveraging California's SB 330 density laws.

By: AXL Media

Published: Mar 10, 2026, 5:37 AM EDT

Source: The Real Deal

The Transition from Office Space to High Density Housing

The proposed development targets the site currently occupied by the Borel Estate Building, a 3 acre property situated near the Hayward Caltrain station. Jemcor Development Partners intends to replace the existing five story structure with two buildings standing eight stories tall. The first building is slated to house 253 market rate apartments, while the second will provide 188 units specifically designated as affordable housing for senior residents. This strategic mix addresses both the general housing shortage and the specific need for subsidized senior living in the Bay Area.

Regulatory Framework and Strategic Positioning

The developer is leveraging Senate Bill 330, a California law designed to accelerate housing production by freezing development fees and preventing local governments from reducing project density. Furthermore, the proposal aligns with San Mateo’s Measure T, a voter approved initiative that removed previous height and density restrictions for properties located near transit corridors. By filing under these specific legal frameworks, Jemcor can bypass traditional bureaucratic hurdles that frequently stall high density projects in suburban California.

Transformative Analysis: A Shift in Suburban Land Use

This project represents a broader structural shift in San Mateo’s urban planning. As the demand for traditional office space softens in a post pandemic economy, suburban office parks are increasingly viewed as underutilized assets. The conversion of the Borel Estate Building—one of the last major holdings of a legacy commercial firm—into a high density residential hub signals a transition from a commercial centric model to a transit oriented residential model. This shift is essential for cities like San Mateo that are facing strict state mandated housing quotas.