Boulder staff present nexus study, propose up-to-$15/sq ft impact fee for large home additions and teardowns

Boulder City Council members on Tuesday reviewed a completed nexus study and staff recommendations for a residential impact fee aimed at offsetting the affordable‑housing impacts of single‑family home teardowns and large additions.

The study, presented by consultant Andrew (Andy) Ratchford of Gruen+Associates and Housing Planner Sloan Wahlberg, estimates that a fee applied to net new above‑ground living area could be justified and recommends a conservative maximum of roughly $15 per added square foot. "We think the fee probably shouldn't be any more than $15 per square foot of additional living space," Ratchford said.

Why it matters: Council directed staff in 2023 to study how demolitions of smaller homes and large additions affect Boulder’s affordable housing supply and needs. Staff say current inclusionary housing rules apply only to new housing, so replacements of existing single‑family homes frequently avoid inclusionary requirements through demolition‑and‑replacement waivers. Kurt Fernhaver, director of Housing and Human Services, said the proposed fee is intended to address that inequity by generating revenue for the city’s Affordable Housing Fund.

Key findings and proposal - The nexus analysis focused on a demand linkage: higher‑priced replacement homes tend to be occupied by…