Is an Engineer Stamp Required for My ADU Project in Louisiana?

Louisiana's municipalities — New Orleans, Baton Rouge, Shreveport, Lafayette — review structural drawings for accessory dwellings under the Louisiana State Uniform Construction Code, and the PE seal is the standard requirement. The seal must show the engineer's name, Louisiana 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 department asks for the seal regardless of who drafted the plans.

The engineer reviews the floor plan and elevations, designs the foundation for soft alluvial soils and the high water table — deep foundations are common in South Louisiana — sizes beams, headers, and the lateral system, and checks hurricane wind, flood, and seismic design. New Orleans flood elevation requirements get extra scrutiny. Garage conversions are checked for floodplain compliance where triggered. Bring the site survey, the geotechnical report, and the architectural plans. Flood elevation is the item most ADU plans miss.

Use this checklist before engaging an engineer for your ADU: • Engineer of record holds an active Louisiana 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 • Flood elevation verified per the flood maps • Foundation designed for soft alluvial soils and the high water table • Garage conversions: existing slab evaluated for dwelling loads • Engineer confirms they'll respond to plan-check corrections on sealed sheets • Seal shows name, Louisiana PE number, and date on every sealed sheet