Historic preservation commission approves revised design for 718 West Ada Street

The Boise City Historic Preservation Commission approved a revised plan for a new residence and accessory dwelling unit at 718 West Ada Street after staff and the applicant said design changes address previously flagged historic‑district guidelines.

The commission voted to approve application DRH24‑00263 with staff recommendations. Commissioner Malloy moved to approve “with the staff's recommendations for approval,” and Commissioner Owens seconded. The roll call vote was five in favor, none opposed.

Staff told the commission the applicant reduced lot coverage to 34–35% (staff calculated 34%), redesigned the accessory dwelling roof to be more congruent with neighboring historic properties, lowered the second‑story massing toward a one‑and‑a‑half‑story form and added tree mitigation measures. Richard, the planning staff presenter, said the revised design dated March 14, 2025, shows the primary residence roof peak at 23 feet 6 inches, similar to adjacent partial two‑story houses, and that shutters would be operable or omitted per guidelines. The accessory structure is under 1,000 square feet and meets height and reduced setback requirements, staff said.

The applicant, Dane Larson, described multiple redesign iterations and said the team reduced the massing of the second story, scaled dormers, and addressed tree mitigation and sewer concerns. Larson said an arborist report identified 30 caliper inches of trees that would be affected by demolition; the plan proposes reusing 18 caliper inches where feasible and planting approximately 12 caliper inches of new Leyland cypress for privacy.

A neighborhood representative, Sandra Herman, thanked the applicant for revisions but questioned staff's method for calculating lot coverage. Herman said staff's percentage rounds acreage and that, using exact lot dimensions, coverage would be 37.3% rather than the staff‑reported 34%. The commission asked staff to note the discrepancy for future discussion of calculation methodology; staff said Ada County records and the department’s current practice produce the acreage percentage used in the report.

Commission discussion focused on whether the revised massing and materials meet the district guidelines; commissioners spoke in favor of the redesign and the applicant’s responsiveness to prior direction. The commission approved the application with the staff conditions on materials and mitigation noted in the staff report.

The commission’s decision is final at this hearing but may be appealed to the Boise City Council if an appeal is filed within 10 days by someone who gave written or oral testimony at the hearing.

Less critical details: staff recommended specific materials and operability of shutters be conditioned; the revised plans include three narrow dormers on the front and rear facades and an attached garage with an ADU above that is one foot seven inches shorter than the primary residence.