Nashua, NH Accessory Structures: Shed Rules (2026)

The Nashua Department of Building Safety administers the NH State Building Code (which adopts the IRC) and Chapter 190 (Land Use Code). The IRC and NH amendments exempt one-story detached residential accessory structures up to 200 sq ft from a building permit when used as a tool shed, playhouse, or similar, with no plumbing or HVAC. However, every shed regardless of size requires a Land Use Permit (zoning sign-off) from the Department of Building Safety to confirm compliance with Nashua zoning — a Building and Land Use Application must be filed with a Plot Plan showing the proposed shed location, dimensions, and setbacks. The Land Use Code Sec. 190-31 (Accessory Buildings) governs detached accessory structures in residential zones, and Sec. 190-16 (Dimensional Regulations) provides the dimensional matrix. Nashua's standard side/rear setback for detached accessory buildings under 200 sq ft in residential zones is 4 ft (a number that aligns with Sec. 190-32's 4 ft side/rear setback for ADUs and that the Nashua zoning practice applies to accessory buildings generally). Accessory structures must sit behind the front facade of the principal building. Maximum height for an accessory structure is typically 18-20 ft in residential zones (less than the principal building). Cumulative accessory structure coverage is subject to the maximum lot coverage of the underlying district (R-40: ~25 percent; R-30: 25 percent; R-18: 30 percent; R-9: 35 percent; R-A: 40 percent; R-B: 50 percent). Larger sheds — over 200 sq ft, or with electrical service, plumbing, or HVAC — require both a building permit and an electrical/plumbing permit through the Department of Building Safety. Sheds must be anchored against wind (Hillsborough County is in the 115 mph basic wind speed zone) and meet the NH State Energy Code if heated. Portable storage containers and PODS are typically allowed only as temporary uses (30-60 days during move-in/move-out or active construction).