{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.timber-roof-truss","code":"thing-q149495","url":"https://ver.cy/models/thing/q149495/","name":"timber roof truss","alternateNames":[],"kind":"thing","status":"research-draft","version":"0.2.0-wave.3","language":"en","classifiers":{"family":"Thing Registry","category":"Physical world and living systems","entryKind":"thing","plane":"PHY","domain":["PHY.BLT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A structural framework of timber members arranged in triangles to support a roof, spanning between walls and carrying the roof covering, in forms from traditional king post, queen post and hammerbeam trusses to modern prefabricated trusses with metal connector plates, and in East Asian carpentry the koyagumi roof framing; timber trusses have been used since antiquity and are designed to codes for load, span and fire.","purpose":"Let an agent explain timber roof trusses and their kinds, relay structural principles and design codes, describe traditional and modern forms including East Asian framing, and distinguish trusses from rafters, purlins and steel trusses.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Triangulation","Timber members and joints","Traditional and prefabricated forms","Code-based design"],"structure":{"bundles":[{"id":"understand","name":"Understand","description":"What a timber truss is.","layers":[{"id":"definition","name":"Definition","description":"Definition and kinds.","findings":[{"id":"definition-finding","name":"Definition","description":"Definition.","questions":[{"text":"What is a timber roof truss, and what kinds exist?","kind":"definition"},{"text":"Is the roof structure a truss, a rafter roof or a steel truss?","kind":"boundary"}]}]},{"id":"mechanics","name":"Mechanics","description":"How trusses work.","findings":[{"id":"mechanics-finding","name":"Mechanics","description":"Mechanics.","questions":[{"text":"How do triangulated members carry roof loads to the walls?","kind":"definition"},{"text":"Which entry fits truss?","kind":"action"}]}]}]},{"id":"design","name":"Design","description":"Design and construction.","layers":[{"id":"codes","name":"Codes","description":"Design codes.","findings":[{"id":"codes-finding","name":"Codes","description":"Codes.","questions":[{"text":"How are timber trusses designed under codes for load, span and fire?","kind":"provenance"},{"text":"Is the question about a specific building, which needs a structural engineer?","kind":"boundary"}]}]},{"id":"prefabricated","name":"Prefabricated","description":"Prefabricated trusses.","findings":[{"id":"prefabricated-finding","name":"Prefabricated","description":"Prefabricated.","questions":[{"text":"How are modern trusses manufactured and installed?","kind":"provenance"},{"text":"Which references are standard?","kind":"provenance"}]}]}]},{"id":"traditions","name":"Traditions","description":"Traditional forms.","layers":[{"id":"european","name":"European","description":"European carpentry.","findings":[{"id":"european-finding","name":"European","description":"European.","questions":[{"text":"What are king post, queen post and hammerbeam trusses, and where are notable examples?","kind":"provenance"},{"text":"Which entry fits hammerbeam roof?","kind":"action"}]}]},{"id":"eastasian","name":"East Asian","description":"East Asian framing.","findings":[{"id":"eastasian-finding","name":"Eastasian","description":"Eastasian.","questions":[{"text":"How does East Asian koyagumi roof framing differ from Western trusses?","kind":"provenance"},{"text":"Which entry fits Japanese carpentry?","kind":"action"}]}]}]},{"id":"care","name":"Care","description":"Conservation and safety.","layers":[{"id":"conservation","name":"Conservation","description":"Conservation.","findings":[{"id":"conservation-finding","name":"Conservation","description":"Conservation.","questions":[{"text":"How are historic timber roofs surveyed and conserved?","kind":"provenance"},{"text":"Which entry fits timber conservation?","kind":"action"}]}]},{"id":"safety","name":"Safety","description":"Safety.","findings":[{"id":"safety-finding","name":"Safety","description":"Safety.","questions":[{"text":"What fire and structural safety issues affect timber roofs?","kind":"provenance"},{"text":"Which sources are cited?","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Describe kinds of timber trusses, from king post to prefabricated trusses.","Report observed decay, damage or added loads to the building owner.","Advise that changes to trusses need a structural engineer."],"mustNot":["Recommend cutting, notching or removing truss members.","Advise loading roof spaces beyond what the trusses were designed for.","Present a damaged or decayed truss as safe.","Recommend alterations to historic roofs without heritage consent where it is required."],"requiresHuman":["Structural alterations to trusses.","Declaring a roof safe after fire, decay or storm damage."]},"ethics":{"considerations":["Truss failure can bring down a roof on occupants.","Historic roofs are irreplaceable heritage."],"affectedParties":["Building occupants","Owners","Workers in roof spaces"]},"owners":{"steward":"The owner of the building; a structural engineer answers for alterations.","roles":[],"masterSystems":["Heritage registers for listed buildings"]},"relations":[{"target":"Q110538923","type":"parent","note":"registry parent class"},{"target":"Q58447637","type":"parent","note":"registry parent class"},{"target":"Q811979","type":"parent","note":"registry parent class"},{"target":"built structure","type":"related","note":"in registry terms"},{"target":"Koyagumi","type":"related","note":"in registry terms, for East Asian forms"},{"target":"truss","type":"related","note":"made of timber"},{"target":"roof","type":"related","note":"the covering"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.timber-roof-truss","Wikidata: Q149495 (https://www.wikidata.org/wiki/Q149495)"]},"properties":{"applicability":"required","items":["typical span of prefabricated trusses: up to about 20 m - residential","hammerbeam span at Westminster Hall: about 20.7 m"]},"recognition":{"applicability":"required","items":["Triangulated timber roof framework","King post, queen post, hammerbeam, prefabricated and East Asian forms","Common rafter roofs lack trusses; steel trusses use metal","A triangulated timber frame with chords and web members, visible in roof spaces and halls."]},"capabilities":{"applicability":"required","items":["explain kinds and principles","relay design codes","describe traditional and modern forms","distinguish from related structures"]},"hazards":{"applicability":"required","items":["Joint failure and decay","Fire","Overloading from added weight","Loss of historic roofs"]},"interfaces":{"applicability":"required","items":["Timber design codes such as Eurocode 5","Prefabricated truss standards","Fire safety rules for timber roofs","Heritage protection of historic roofs"]},"context":{"applicability":"required","items":["Supporting roofs over spans.","king post and queen post trusses","hammerbeam and other medieval trusses","prefabricated trusses with connector plates","scissor and attic trusses","East Asian koyagumi roof framing","glulam and engineered timber trusses"]}},"sources":[],"openQuestions":["Should hammerbeam roof be a separate entry?","How should design codes be linked?","How should East Asian framing be cross-referenced?"],"resources":{"spec":"/models/things/publications/thing-q149495/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q149495/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T23:41:50Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"filled","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"missing"},"notes":{"sources":"Written from model knowledge without web access; claims are unverified."},"score":0.941}}