Committee to refine resiliency code: staff proposes keeping minimum unit sizes, removing average requirement as optional with anti‑STR covenant; understory home

Planning staff briefed the Land Use and Sustainability Committee on proposed amendments to the city’s resiliency and unit‑size rules and described a path to reconcile concerns raised at the prior Commission meeting.

Key points: Staff proposed leaving the existing minimum unit sizes in place (550 square feet for market‑rate units; 400 square feet for workforce/affordable units) while removing the current administrative average‑unit‑size requirement (800 square feet average for market projects). Staff said the change would increase flexibility for attainable and workforce‑adjacent units but noted a primary concern raised in the prior meeting is that smaller units could convert to short‑term rentals. To address that, staff proposed an optional program: an applicant could remove the average requirement only by voluntarily recording a covenant prohibiting short‑term rentals for the project. Planning staff suggested an additional review layer—such as Planning Board review or another discretionary check—if applicants seek to use the optional path.

Why it matters: Under the current code, two standards apply: a market‑rate minimum unit size of 550 sq ft and an 800‑sq‑ft average unit size. Developers say the average requirement can force them to include larger “luxury” units to raise the average, undermining attainable unit production. Opponents worry that removing the average could cause an influx of small units used as short‑term rentals rather than housing for year‑round residents.

Sample analysis: Staff modeled typical lot sizes in Arm 1, Arm 2 and Arm 3 districts and concluded that even if a developer built the smallest allowed market units (all 550 sq ft), available FAR and density caps would in many cases limit the ability to use all remaining FAR to add unlimited small units; in practice, staff said, it is unlikely developers would build exclusively at the minimum unit size. Staff therefore proposed making removal of the average optional and linked to a covenant against short‑term rentals.

Understory homes: Planning staff also discussed understory (raised) single‑family homes, which can provide resilience benefits by elevating living floors and improving ground‑level pervious area. Staff said current code tends to allow certain houses to be approved administratively (resulting in higher finished yard elevations) while understory designs must go to the Design Review Board (DRB) and therefore add time and cost. Staff recommended ways to encourage understory approaches while keeping DRB oversight to ensure design compatibility; staff noted the DRB process can be expensive and time consuming and proposed outreach and code changes to reduce barriers to well‑designed understory homes.

Next steps: Committee members asked staff to meet with colleagues who had raised concerns at the previous meeting, to refine the covenant/optional path and to consider an additional review step if applicants seek to use the average‑removal option. Staff will return revised language and outreach recommendations to the Commission.