New Castle County sets building height limits by zoning district under UDC Article 40. Residential districts typically allow 35 ft or 2.5 stories for single-family homes. Commercial and mixed-use districts allow 45 to 75+ ft depending on location. Height measured from average finished grade. Chimneys, antennas, and mechanical screens have limited exceptions. Airport approach zones near ILG and Summit add FAA Part 77 restrictions.
Building and structure heights in New Castle County are regulated by the UDC Article 40 zoning code. Typical residential height limits: S and SR (Suburban/Suburban Reserve): 35 ft or 2.5 stories; NC5: 35 ft or 2.5 stories; NC6a: 35 ft; NC6b: 35 ft; NC10: 40 ft for multifamily; NC21: 45 to 60 ft in mixed-use overlays. Commercial (CR - Commercial Regional): typically 45 to 60 ft. OR and HI (Office/Industrial): 45 to 75+ ft with setback-to-height ratios. Height is measured from average finished grade at the building to the highest point of the roof (peak of pitched roof, parapet of flat roof). Exempt features with limits include chimneys (typically 3 ft above roof), HVAC screens, antennas, and solar arrays (subject to UDC solar provisions). Airport approach zones near Wilmington Airport (ILG), New Castle County Airport (KILG, same facility), and Summit Airport (KEVY) impose FAA Part 77 height restrictions on structures within approach surfaces. Historic district overlays in parts of New Castle (the town) and in design-review districts may impose lower maximums. Planned Unit Developments (PUDs) can negotiate alternative heights through master plans. Height variances require Board of Adjustment hearing. Tall communications towers require separate siting approvals under the Telecommunications Act and UDC.
Exceeding height limit without variance: stop-work order, required reduction, or variance application. Fines $250 to $2,000. Airport zone violation: additional FAA enforcement and potential injunction. Historic district height violation: correction required and fines under UDC plus state historic preservation rules.
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See how Wilmington's structure height limits rules stack up against other locations.
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