Chicago always requires a building permit for structural porch or deck work; routine maintenance and qualifying nonstructural repairs can be permit-exempt.
A permit is also required when a violation notice says so. Height, landing area, structural elements, egress, landmarks, zoning, and existing permit status remain separate.
What this tells youComputed rule answer
How precise this isComputed rule answer
Official data checkedChicago porch and deck safety
Next stepCheck official deck/accessory-structure rules with deck dimensions and height.
Permit always requiredRepair or replacement of columns, beams, foundations, stringers, floor joists, or other structural elements
No permit for routine workPainting, power washing, and qualifying nonstructural repair when no violation requires a permit
Limited porch exceptionQualifying residential porch under 6 ft with no more than 50 sq ft of landing area