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

Nebraska's municipalities — Omaha, Lincoln, Bellevue, Grand Island — review structural drawings for accessory dwellings, and the PE seal is the standard requirement. The seal must show the engineer's name, Nebraska 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 below the frost line — expansive Pierre shale gets extra attention in the west — sizes beams, headers, and the lateral system, and checks snow, wind, and seismic design. Garage conversions get extra scrutiny because the existing slab was rarely designed as a dwelling foundation. Loess soils are checked where triggered. Bring the site survey, the geotechnical report, and the architectural plans. Soil movement design is the item most ADU plans miss.

Use this checklist before engaging an engineer for your ADU: • Engineer of record holds an active Nebraska PE license, verifiable on the state roster • Dimensioned floor plan and elevations ready for structural review • Site survey showing setbacks, easements, and existing structures • Geotechnical report addressing Pierre shale or loess soils for the lot • Foundation designed for soil movement, not just bearing capacity • Garage conversions: existing slab evaluated for dwelling loads • Engineer confirms they'll respond to plan-check corrections on sealed sheets • Seal shows name, Nebraska PE number, and date on every sealed sheet