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

Section 174-8.2(D)(4) sets the maximum height in the Residence A district at 35 feet, 2 1/2 stories, with 17 feet and one story for accessory buildings. Section 174-8.3(D)(4) repeats the same figures for the Residence B district. For lots laid out and recorded in Residence B districts before the 1966 discontinuance of Residence C districts, § 174-8.3(E)(4) keeps the 35 feet, 2 1/2 stories limit and restricts accessory buildings to one story.

Chapter 174 measures height by a defined method. HEIGHT is the vertical difference between the average of the mean finished ground elevations of all sides of the building or structure and the elevation of the highest point of the roof for flat roofs, to the deckline of mansard roofs and to the mean height between eaves and ridge for gable, hip and gambrel roofs. That means a pitched roof is measured to the point midway between eaves and ridge rather than to the peak.

The definition excludes signs and the structural features exempt under § 174-15 that extend not more than 20 feet above the permitted height. Section 174-15 explains that the height limitations of the schedule do not apply to antennas, chimneys, silos, skylights, tanks, towers, ventilators and similar building features extending not more than 20 feet above the height permitted in the district in which they are located and not used for human occupancy.

The height definition also contains a grading rule for buildings subject to site plan approval under § 174-10: the average finished ground elevation shall not be raised above the original natural ground through fill or regrading to more than two feet above the center-line grade of the frontage street opposite the proposed building, unless the approved site plan provides for such buildup. Height sits alongside the setback, lot area and floor area ratio standards listed in the same subsection of each residential district.