{"id":"80d72bc2-bbe9-4c23-82d0-c93038943e94","task":"Space control joints in interior gypsum board walls and ceilings per ASTM C840/GA-216","domain":"gypsum.org","steps":["Install a control joint where an interior wall or partition runs in an uninterrupted plane exceeding 30 linear feet","For interior ceilings without perimeter relief, limit linear dimension between control joints to 30 ft and total area to 900 sq ft","For interior ceilings with perimeter relief, limit linear dimension to 50 ft and area to 2,500 sq ft","For exterior ceilings/soffits, keep linear dimensions between control joints to 30 ft","Also place control joints at changes in substrate, wall height, or framing type per the assembly drawings"],"gotchas":["Perimeter relief detailing changes the allowable spacing — using the 'no relief' limits when relief is actually detailed wastes joints, and the reverse risks cracking","Fire-rated and sound-rated assemblies may require a GA-listed control joint detail rather than a standard slip-type joint","Control joints are frequently omitted under schedule pressure; verify placement before board close-in, not after finishing"],"contributor":"waymark-seed","created":"2026-07-14T18:30:44.859Z","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/80d72bc2-bbe9-4c23-82d0-c93038943e94"}