Section 311 Neighborhood Notification is required in three situations tied to where the project is and what it does: (1) Within the Priority Equity Geographies Special Use District, any planning entitlement application in Residential, NC, NCT, Chinatown Mixed Use, and Eastern Neighborhoods Mixed Use Districts for demolition, new construction, or alteration of buildings is subject to notice, except Accessory Dwelling Units under § 207.2 and a change of use to a principally permitted use in Western SoMa, Central SoMa, or East SoMa, which are not subject to this section (§ 311(b)(1) ). (2) In RH districts within the Family Housing Opportunity SUD, projects that do not meet § 249.94(c) follow the “all other projects” triggers below (§ 311(b)(2) ). (3) In all other Residential, NC, NCT, and Eastern Neighborhoods Mixed Use Districts, notice is required for: any vertical alteration, unless at least one new dwelling unit is added; any alteration to a one‑unit building that both increases Gross Floor Area by at least 25% and results in GFA greater than 3,000 square feet; and any demolition or new construction that does not add at least one new dwelling unit (§ 311(b)(3)(A)–(C) and (b)(4) ). For § 311 purposes, an “alteration” means an increase to the exterior dimensions of a building, excluding features listed in § 136(c)(1)–(26) (§ 311(b)(4) ).
What counts as a “vertical alteration”
A vertical alteration includes, for example, adding a full new floor; increasing the actual or measured roof height; converting a sloped roof to a higher flat roof; adding a stair/elevator penthouse; or adding other roof‑level enclosures beyond items exempt from height measurement. Horizontal expansions at an existing enclosed floor are not “vertical alterations” (§ 311(b)(3)(A) interpretation ).
Subterranean work and the 25%/3,000 sf trigger (outside PEG SUD)
Purely subterranean additions do not trigger notice under § 311(b)(3)(B) because they are not “alterations” to exterior dimensions. But if a project combines above‑grade alteration with a new basement, the total GFA (including the basement) is used to test the 25% and 3,000 square feet thresholds (§ 311(b)(3)(B) interpretations ).
Common exemptions and edge cases
- ADUs: Projects to construct an ADU under § 207.2 are not subject to § 311 notice (§ 311(b)(1) ).
- Permitted obstructions: Code‑complying features in § 136(c)(1)–(26) do not count as “alterations,” whether or not in required setbacks; outside PEG SUD they rarely trigger notice on their own (§ 311(b)(4) and interpretation ).
- Lightwell infills: No 311 if the infill is against a blank wall and not visible off‑site; limited neighbor notice if visible only to the adjoining property; full § 311 if visible from other off‑site locations (interpretation ).
- Decks: Unenclosed decks and stairs are not “buildings,” so they generally do not require § 311; multi‑level, supported decks or those triggering specific building‑code fire‑wall conditions can require notice (interpretation; includes examples such as 10 feet above grade).