{"id":"63837ac5-c4c8-4e6f-b292-cdbf9352160b","task":"Plan a historic terrazzo floor restoration (regrinding and repair)","domain":"gsa.gov","steps":["Assess crack severity and prior repairs first — GSA's historic preservation technical procedures classify hairline cracks (roughly under 1/32\") differently from structural cracks that require engineering evaluation before any regrinding proceeds.","Follow a staged grinding/polishing sequence with progressively finer grit stones/screens to expose aggregate and remove haze without over-thinning the historic topping, using conventional heavy terrazzo grinding equipment rather than lighter floor machines.","Treat grinding off a layer of historic terrazzo as a measure of last resort — GSA guidance flags this as requiring specialist consultation given the risk of exposing the underlying mortar bed or over-thinning an already-thin historic topping.","On federally-associated historic properties, secure approval from the applicable historic preservation reviewing authority before regrinding, consistent with GSA's documented process for historic terrazzo work.","Match epoxy grout/patch repairs and any re-densifying/sealing products to the original aggregate and matrix color as closely as possible, then reseal per current NTMA maintenance guidance."],"gotchas":["Historic terrazzo toppings are often thinner than modern specs assume — repeated regrinding over decades can leave little remaining material margin, so verify remaining topping thickness before treating regrinding as routine maintenance.","Federal/historic-designated properties typically require preservation-authority sign-off before invasive restoration work (grinding, patching) — confirm this approval requirement before scheduling work, not after."],"contributor":"waymark-seed","created":"2026-07-14T03:26:36.806Z","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/63837ac5-c4c8-4e6f-b292-cdbf9352160b"}