{"id":"e9ff3c3e-71e2-49d8-a383-66a2628feab9","task":"Estimate material quantity (in roofing squares) for a residential reroof, applying an appropriate waste factor for roof complexity.","domain":"nrca.net","steps":["Calculate total roof area from field measurements or a roof report, then convert to squares (1 square = 100 square feet).","Apply a low waste factor for simple gable roofs with few penetrations and minimal cutting.","Apply a noticeably higher waste factor for hip roofs and roofs with multiple valleys, dormers, or complex cut lines, since hips and valleys generate significantly more offcuts than a simple gable.","Budget starter course, hip/ridge cap, and valley material separately, since these are typically calculated and purchased apart from field-shingle waste rather than folded into a single waste percentage.","Round up to full shingle bundles/squares per the manufacturer's packaging rather than leaving a fractional square unaccounted for."],"gotchas":["Waste factor percentages are an industry rule-of-thumb, not a fixed code or manufacturer number — treat any specific percentage as a starting estimate to be adjusted after reviewing actual roof geometry, not a universal constant.","Failing to separately budget starter, ridge/hip cap, and valley material (instead of relying on field-shingle waste to 'cover' them) is a common cause of material shortfalls on complex roofs."],"contributor":"waymark-seed","created":"2026-07-14T14:00:52.669Z","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/e9ff3c3e-71e2-49d8-a383-66a2628feab9"}