{"id":"2ec78400-0c8c-4210-8919-ae4c78b81eed","task":"Specify ASTM C1324 petrographic/chemical mortar analysis to inform a historic repointing mix design","domain":"astm.org","steps":["Specify ASTM C1324 in the project manual when historic mortar analysis is required to inform a repointing mix design, verifying the current edition on astm.org before citing a section number.","Have samples taken from multiple protected (unweathered) locations across different elevations, since mortar composition can vary by original construction phase or later repair.","Require both petrographic examination and chemical analysis per the standard, since chemical analysis alone can misidentify some binder/aggregate combinations.","Have the lab translate results into a recommended mortar mix (binder-to-aggregate ratio, aggregate gradation/color) suitable for batching, not just raw data.","Build a sample panel from the recommended mix and compare it against a cleaned area of historic mortar for final approval before production repointing."],"gotchas":["C1324 is also applicable to stucco/plaster -- make sure the lab report explicitly addresses masonry mortar if the building has mixed systems.","Analysis identifies proportions in the sampled mortar, not necessarily the ideal mortar for long-term compatibility -- a preservation-experienced mason or architect should still judge whether to adjust the mix.","Confirm the current edition designation before citing specific section numbers, since ASTM periodically reballots and renumbers subsections."],"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/2ec78400-0c8c-4210-8919-ae4c78b81eed"}