Garage Conversions: Manchester vs Nashua

Can I convert my garage to a bedroom?

Yes, with a building permit. The space must meet habitable standards including insulation, egress windows, and fire separation.

Will I need to replace lost parking spaces?

Check Manchester zoning. If the garage provided required off-street parking, replacement spaces may be needed.

Can I convert my Nashua garage to an in-law suite or apartment?

Yes, and the new NH ADU law strongly favors it. Pull a building permit and electrical permit from the Nashua Department of Building Safety. The space must meet the NH State Building Code: 7 ft ceiling height, egress windows from sleeping rooms (5.7 sq ft openable, 24 in height, 20 in width), interconnected smoke alarms, CO alarms, and NH Energy Code insulation. If you add a kitchen and separate entrance the result is an Accessory Dwelling Unit governed by NH RSA 674:71-:73 (HB 577, effective 7/1/2025). Importantly, Nashua must permit the conversion by-right even if the existing garage does not meet current setbacks — RSA 674:72 expressly preserves existing-structure conversions regardless of dimensional nonconformity.

Do I have to add parking when I convert my Nashua garage?

Possibly one space. NH RSA 674:72 allows a municipality to require one additional off-street parking space for an ADU. Nashua may require that replacement space be added as a paved or gravel pad on the driveway if the converted garage was previously the principal parking. The state law does not allow Nashua to require more than one additional space, and the space may be tandem with existing driveway parking. Confirm specifics with the Nashua Planning Department before final design.