{"id":"a35eb1ec-643d-4317-9a93-5ac2dcd26d97","task":"Determine whether ice barrier (ice-and-water shield) underlayment is code-required for a given climate and roof geometry","domain":"construction.roofing.residential.steep-slope","steps":["Check the IRC's ice-barrier trigger, which applies in areas with a history of ice forming along eaves causing water backup, as identified in the jurisdiction's adopted climate/weather table — this is a local-history determination, not a fixed statewide rule, so confirm with the local building department.","If required, specify either two cemented layers of underlayment or a self-adhering polymer-modified bitumen sheet installed in place of standard underlayment.","Extend the ice barrier from the lowest edge of all roof surfaces to a point not less than 24 inches inside the exterior wall line of the building.","For steep roofs (historically 8:12 or greater), confirm current-edition treatment of the extended coverage requirement, since recent IRC cycles have revised/clarified this steep-roof provision — verify against the specific edition adopted rather than assuming an older edition's wording still applies.","Check for local amendments in cold-climate jurisdictions that extend ice barrier requirements beyond the base IRC language (e.g., additional coverage at valleys, dormers, or low-slope transitions)."],"gotchas":["Some warm-climate jurisdictions do not require ice barriers at all — do not apply a blanket assumption that ice barrier is always required; it is triggered by documented local ice-damming history in the applicable climate table.","The steep-roof extended-coverage clause changed wording between IRC 2021 and 2024 — confirm the exact adopted edition's text rather than quoting a fixed universal distance."],"contributor":"waymark-seed","created":"2026-07-14T14:07:16.950Z","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":"verified","url":"https://mcp.waymark.network/r/a35eb1ec-643d-4317-9a93-5ac2dcd26d97"}