Commission defers new-construction plans for 718 W. Ada; asks for true 1½‑story massing, tree mitigation and privacy measures

The Boise City Historic Preservation Commission on Dec. 9 deferred consideration of a proposed new 1½‑story residence with an ADU at 718 West Ada Street and told the designer to return with revisions that make the house’s massing closer to a true one‑and‑a‑half‑story form, include a detailed tree mitigation plan specifying caliper inches removed and replaced, and propose measures to protect neighbors’ privacy.

Staff presented the resubmittal and noted the applicant had reduced lot coverage to 35 percent, increased the accessory dwelling unit’s roof pitch and reduced the ADU depth so the overall footprint would meet the city’s guideline threshold. Staff said the new drawings show the primary residence’s roof peak at 25 feet, 8 inches and that the accessory structure would be shorter than the primary residence. Staff concluded materials and openings can be conditioned to meet district guidelines and recommended approval in the resubmittal report.

Commissioners, neighborhood representatives and nearby residents raised several concerns. Suzanne Veil, speaking for the registered neighborhood association, questioned the lot coverage calculation; she said the applicant’s site plan indicated a 50-by-80-foot lot (4,000 sq. ft.) and calculated coverage at about 39.2 percent, while staff used an assessor acreage number that produced 36 percent. Veil asked which lot-square-footage source the commission intends to use for future calculations and requested the tree mitigation plan be a condition of approval with specific caliper-inch numbers.

Nearby resident Gretchen Riley of 720 West Ada said the proposals raised privacy and daylight concerns because the new house’s side elevation and dormers would be close to her kitchen and living-room windows. Designer Dane Larson said the team had reduced porch size and ADU depth, increased pitch, and adjusted the footprint to meet the 35 percent lot-coverage target; he also said they will evaluate caliper-inch totals and were willing to work on tree protection fencing (including on neighboring properties with permission).

Commission discussion focused on whether the revised design still read as a full two‑story mass because of wide dormers and unbroken front wall planes. Commissioners requested changes that could include narrowing dormer width, introducing step‑backs in the second floor to break up the front façade, and additional context or three‑dimensional renderings to demonstrate congruity with adjacent one‑ and one‑and‑a‑half‑story houses. Commissioners also asked for a clearer tree mitigation plan (listing caliper inches removed and replacement strategy), clarification about lot-square-footage source for lot‑coverage calculations, and privacy mitigations (vegetation or adjusted window placement).

A motion to defer DRH24-00263 for revisions carried on roll call: Montoto — Aye; Malloy — Aye; Parks — Aye; Owens — Aye; Sales — Aye; Moore — Aye. The commission instructed the applicant to work with staff on changes to massing, to submit a tree mitigation plan specifying caliper inches to be removed and replaced, and to propose measures for neighbor privacy. The application remains postponed to the commission’s next monthly hearing.