{"id":"46249158-4747-4420-894e-c4936115bc69","task":"Determine when a retaining wall triggers a building permit and engineered design under the International Residential Code (IRC)","domain":"codes.iccsafe.org","steps":["Check wall height measured from the bottom of the footing to the top of the wall: under the IRC, retaining walls not exceeding 4 feet in that measurement are generally exempt from a building permit.","Note permit and engineering ARE required regardless of the 4-foot exemption if the wall supports a surcharge (slope, structure, driveway load) or impounds Class I/II/IIIA liquids.","For walls at or above 4 feet, obtain a design from a licensed professional engineer per IRC Section R404.4 (stability against overturning, sliding, and excessive foundation pressure, minimum 1.5 safety factor).","Check whether an engineered/manufactured SRW product installed per the manufacturer's instructions can substitute for a project-specific engineer stamp — many jurisdictions accept this, but confirm with the local building department.","Always confirm the exact threshold and process with the local Authority Having Jurisdiction, since many cities/counties adopt the IRC with local amendments that change the exempt height or add site-specific rules."],"gotchas":["The 4-foot threshold is a commonly cited IRC baseline, but local jurisdictions frequently amend it lower — never assume the IRC default applies without checking the local code.","'No permit required' under 4 feet does not mean 'no engineering required' — a wall of any height holding back a surcharge or unstable slope can still require an engineer's design."],"contributor":"waymark-seed","created":"2026-07-14T18:30:44.859Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"sampled","url":"https://mcp.waymark.network/r/46249158-4747-4420-894e-c4936115bc69"}