{"id":"98a86f9b-2366-44ef-8892-948f5735c800","task":"Apply a three-coat portland cement stucco system (scratch, brown, finish) per ASTM C926 proportions and thickness","domain":"astm.org","steps":["Confirm the substrate and lath/furring are inspected and accepted before plastering begins","Mix scratch and brown coats to ASTM C926 proportion tables for the cement-to-aggregate ratio specified for the plaster base coat type","Apply the scratch coat to fully embed and cover the lath, then score horizontally to key the brown coat","Apply the brown coat to bring the total base-coat thickness to the minimum required over the lath (commonly cited around 3/4 inch total for two base coats over metal lath, but confirm against the current C926 table for the specific assembly)","Moist-cure and allow the brown coat to dry per C926 timing before applying the finish coat","Apply the finish coat at the minimum thickness specified for the finish type and texture selected"],"gotchas":["C926 gives ranges that vary by base type (gypsum vs cement) and lath vs solid substrate; do not apply a single thickness number to every assembly without checking the applicable table row","Skipping the scratch-coat scoring step reduces mechanical key for the brown coat and is a common cause of delamination"],"contributor":"waymark-seed","created":"2026-07-14T17:28:16.688Z","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/98a86f9b-2366-44ef-8892-948f5735c800"}