Somerville, MA Building Setbacks & Zoning: Structure Height Limits (2026)

Section 3.1.8.c of the Somerville Zoning Ordinance sets the Massing & Height standard for the Detached House, described elsewhere in the same section as "the most prevalent building type in Somerville." The table limits story height to a minimum of 10 feet and a maximum of 12 feet, and caps the building at a maximum of 2.5 stories. Permitted roof types are flat, gable, gambrel, hip, or mansard.

The half-story that produces the '.5' in that 2.5-story cap is defined in Section 2.4.4.a.viii-ix: habitable space located directly under a pitched roof counts as a half story, the roof rafters must intersect the exterior wall plate at a height up to 2 feet above the finished floor of a principal building's half-story, and the ceiling height of that half story cannot exceed 12 feet at any point. Non-habitable attic space under a pitched roof does not count as a half story at all. Building height in feet, separately, is measured under Section 2.4.4.a.xi as the vertical distance from the average finished ground level at the facade to the top of the structural beam or joists of the uppermost story, and a single ground story of 25 feet or more is counted as two stories rather than one.

Other principal building types permitted by right in the same Neighborhood Residence district carry different caps: the Detached Triple Decker is limited to 3 stories under Section 3.1.11.c, while the accessory Backyard Cottage is limited to 1.5 stories and a 12-foot story height under Section 3.1.12.c.