Zoning board grants variance to allow ADU above garage at 521 Mountain Road

The Goffstown Zoning Board of Adjustment on June 2 granted a variance that allows an accessory dwelling unit (ADU) to be built above a garage at 521 Mountain Road, a 1.25-acre lot in a zone whose dimensional table requires a 5-acre minimum.

The applicant, listed in the agenda as Sandra Brown Revocable Trust and Lawrence Brown, sought relief under section 5.2.7 of the zoning ordinance to place an ADU above an expanded garage on a nonconforming lot of record. The board approved the request after deliberations that focused on whether the hardship arises from the property's condition or from the town's ordinance.

The applicant described the project as increasing the garage to a three-stall configuration with a dormer-style ADU above it; the applicant estimated living area for the ADU at about 950 square feet. Board members and staff reviewed dimensions and coverage calculations: the proposed footprint (including a 16-foot addition) was discussed as roughly 44 by 28 feet (about 1,232 sq ft), and the maximum allowed building coverage for the lot (5%) was calculated at about 2,722 sq ft — the board concluded coverage would remain under that limit. Jack Shepard, the building inspector, summarized the zoning relationship between the structure and the lot: "The structure is conforming as it is, but it's the lot size itself of the parcel that is non-conforming," and noted that setbacks shown on the sketch exceed the 50-foot side-yard requirement.

Board members also examined whether the existing septic system would support another bedroom. The parcel currently has a septic sized for a three-bedroom house; options discussed included redesigning the septic to serve four bedrooms as part of the building permit process or converting an existing bedroom to non-bedroom use so the system remains a three-bedroom design.

Deliberations centered on the variance criteria in section 5.2. Board members repeatedly noted ambiguity introduced by recent state ADU legislation (discussed as HB577 and related RSA provisions) and concluded the hardship in this case derives from the town's dimensional requirement for ADUs on substandard lots of record, not from the applicants' actions. A motion to grant the variance was made by Bruce Bick and seconded by John Delivo; one member voiced opposition and the motion carried. The board noted that the ADU must meet the town's ADU supplemental standards and that the ADU cannot exceed 950 square feet without a separate variance.

The board closed the public hearing and entered deliberative session before voting. The applicant thanked the board after the decision.

What happens next: the decision is subject to the town's rehearing and appeal rules; any party aggrieved by the ZBA decision has 30 days to request a rehearing before pursuing a court or appeals board process.