Plan Review and Permitting
Permits and the exemption trap
A permit is required before construction, alteration, repair, demolition, or change of use unless the work appears on the exemption list (IBC 105.2 / IRC R105.2). The classic trap: exemption from a permit is not exemption from the code. An exempt shed still must satisfy structural, egress, and zoning requirements.
Thresholds differ between the codes and are frequent exam items. The IBC exempts one-story detached accessory structures with floor area not over 120 square feet; the IRC exempts comparable structures with projected roof area not over 200 square feet. Fences not over 6 feet, retaining walls not over 4 feet carrying no surcharge, and ordinary finish work such as painting or tiling are commonly exempt. Decks, new roof coverings, and most structural replacements are not.
Submittal documents
The building official decides what must be submitted (IBC 107). Documents must be clear enough to show the nature and extent of the work and must be prepared and sealed by a registered design professional where law requires. Deferred submittals - items designed after permit issuance, such as pre-engineered trusses - must be identified and approved. Changed plans require re-submittal; field departures from approved documents are violations even if the work otherwise complies.
Permit lifecycle
Permits become invalid if work does not commence within 180 days, or if work is suspended or abandoned for 180 days; extensions are discretionary. The permit or placard must be displayed, and work must match the approved documents.
Worked example
A 10 ft by 12 ft detached shed is 120 square feet: exempt under the IBC floor-area threshold, but not automatically under the IRC's 200-square-foot projected-roof-area test.