Is an Engineer Stamp Required for My ADU Project in Rhode Island?

Rhode Island's municipalities — Providence, Warwick, Cranston, Pawtucket — review structural drawings for accessory dwellings under the Rhode Island State Building Code, and the PE seal is the standard requirement. The seal must show the engineer's name, Rhode Island PE number, and date, and the engineer must be in responsible charge of the engineering. Detached ADUs, garage conversions, and in-law additions are treated the same at the structural level. Owner-builders don't escape the requirement: the building official asks for the seal regardless of who drafted the plans.

The engineer reviews the floor plan and elevations, designs the foundation below the frost line, sizes beams, headers, and the lateral system, and checks coastal wind, snow, and flood design per the Rhode Island State Building Code. Properties near Narragansett Bay and the shore get extra scrutiny for flood elevation and opening protection. Garage conversions are checked for floodplain compliance where triggered. Bring the site survey, the geotechnical report, and the architectural plans. Flood design is the item most ADU plans miss.

Use this checklist before engaging an engineer for your ADU: • Engineer of record holds an active Rhode Island PE license, verifiable on the state roster • Dimensioned floor plan and elevations ready for structural review • Site survey showing setbacks, easements, flood zone, and existing structures • Coastal wind and flood design verified where triggered • Frost-depth compliance verified for footings, plumbing, and equipment • Garage conversions: existing slab evaluated for dwelling loads • Engineer confirms they'll respond to plan-check corrections on sealed sheets • Seal shows name, Rhode Island PE number, and date on every sealed sheet