IFC 4.3.2.20250123 (IFC4X3_ADD2) under development

6.1.3.31 IfcRoof

6.1.3.31.1 Semantic definition

A roof is the covering of the top part of a building, it protects the building against the effects of weather.

The IfcRoof shall either be represented:

  • as a roof assembly that aggregates all parts (slabs, rafters and purlins, or other included roofs, such as dormers) with own shape representation, or
  • as a single roof without decomposition including all shape representations directly at the roof entity.

6.1.3.31.2 Entity inheritance

6.1.3.31.3 Attributes

# Attribute Type Description
IfcRoot (4)
IfcObjectDefinition (7)
IfcObject (5)
IfcProduct (5)
IfcElement (13)
Click to show 34 hidden inherited attributes
IfcRoof (1)
9 PredefinedType OPTIONAL IfcRoofTypeEnum

Predefined generic types for a roof that are specified in an enumeration. There may be a property set given for the predefined types.

Table 6.1.3.31.E

6.1.3.31.4 Formal propositions

Name Description
CorrectPredefinedType

Either the PredefinedType attribute is unset (e.g. because an IfcRoofType is associated), or the inherited attribute ObjectType shall be provided, if the PredefinedType is set to USERDEFINED.

NOT(EXISTS(PredefinedType)) OR
(PredefinedType <> IfcRoofTypeEnum.USERDEFINED) OR
((PredefinedType = IfcRoofTypeEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType))
CorrectTypeAssigned

Either there is no roof type object associated, i.e. the IsTypedBy inverse relationship is not provided, or the associated type object has to be of type IfcRoofType.

(SIZEOF(IsTypedBy) = 0) OR
('IFC4X3_DEV_54a9de1b.IFCROOFTYPE' IN TYPEOF(SELF\IfcObject.IsTypedBy[1].RelatingType))
Table 6.1.3.31.F

6.1.3.31.5 Property sets

  • Pset_ConcreteElementGeneral
    • AssemblyPlace
    • CastingMethod
    • StructuralClass
    • StrengthClass
    • ExposureClass
    • ReinforcementVolumeRatio
    • ReinforcementAreaRatio
    • DimensionalAccuracyClass
    • ConstructionToleranceClass
    • ConcreteCover
    • ConcreteCoverAtMainBars
    • ConcreteCoverAtLinks
    • ReinforcementStrengthClass
  • Pset_Condition
    • AssessmentDate
    • AssessmentCondition
    • AssessmentDescription
    • AssessmentType
    • AssessmentMethod
    • LastAssessmentReport
    • NextAssessmentDate
    • AssessmentFrequency
  • Pset_ConstructionAdministration
    • ProcurementMethod
    • SpecificationSectionNumber
    • SubmittalIdentifer
  • Pset_ConstructionOccurence
    • InstallationDate
    • ModelNumber
    • TagNumber
    • AssetIdentifier
  • Pset_ElementKinematics
    • CyclicPath
    • CyclicRange
    • LinearPath
    • LinearRange
    • MaximumAngularVelocity
    • MaximumConstantSpeed
    • MinimumTime
  • Pset_EnvironmentalCondition
    • ReferenceAirRelativeHumidity
    • ReferenceEnvironmentTemperature
    • MaximumAtmosphericPressure
    • StorageTemperatureRange
    • MaximumWindSpeed
    • OperationalTemperatureRange
    • MaximumRainIntensity
    • SaltMistLevel
    • SeismicResistance
    • SmokeLevel
    • MaximumSolarRadiation
  • Pset_EnvironmentalImpactIndicators
    • Reference
    • FunctionalUnitReference
    • IndicatorsUnit
    • LifeCyclePhase
    • ExpectedServiceLife
    • TotalPrimaryEnergyConsumptionPerUnit
    • WaterConsumptionPerUnit
    • HazardousWastePerUnit
    • NonHazardousWastePerUnit
    • ClimateChangePerUnit
    • AtmosphericAcidificationPerUnit
    • RenewableEnergyConsumptionPerUnit
    • NonRenewableEnergyConsumptionPerUnit
    • ResourceDepletionPerUnit
    • InertWastePerUnit
    • RadioactiveWastePerUnit
    • StratosphericOzoneLayerDestructionPerUnit
    • PhotochemicalOzoneFormationPerUnit
    • EutrophicationPerUnit
  • Pset_EnvironmentalImpactValues
    • TotalPrimaryEnergyConsumption
    • WaterConsumption
    • HazardousWaste
    • NonHazardousWaste
    • ClimateChange
    • AtmosphericAcidification
    • RenewableEnergyConsumption
    • NonRenewableEnergyConsumption
    • ResourceDepletion
    • InertWaste
    • RadioactiveWaste
    • StratosphericOzoneLayerDestruction
    • PhotochemicalOzoneFormation
    • Eutrophication
    • LeadInTime
    • Duration
    • LeadOutTime
  • Pset_InstallationOccurrence
    • InstallationDate
    • AcceptanceDate
    • PutIntoOperationDate
  • Pset_MaintenanceStrategy
    • AssetCriticality
    • AssetFrailty
    • AssetPriority
    • MonitoringType
    • AccidentResponse
  • Pset_MaintenanceTriggerCondition
    • ConditionTargetPerformance
    • ConditionMaintenanceLevel
    • ConditionReplacementLevel
    • ConditionDisposalLevel
  • Pset_MaintenanceTriggerDuration
    • DurationTargetPerformance
    • DurationMaintenanceLevel
    • DurationReplacementLevel
    • DurationDisposalLevel
  • Pset_MaintenanceTriggerPerformance
    • TargetPerformance
    • PerformanceMaintenanceLevel
    • ReplacementLevel
    • DisposalLevel
  • Pset_ManufacturerOccurrence
    • AcquisitionDate
    • BarCode
    • SerialNumber
    • BatchReference
    • AssemblyPlace
    • ManufacturingDate
  • Pset_ManufacturerTypeInformation
    • GlobalTradeItemNumber
    • ArticleNumber
    • ModelReference
    • ModelLabel
    • Manufacturer
    • ProductionYear
    • AssemblyPlace
    • OperationalDocument
    • SafetyDocument
    • PerformanceCertificate
  • Pset_PrecastConcreteElementFabrication
    • TypeDesignation
    • ProductionLotId
    • SerialNumber
    • PieceMark
    • AsBuiltLocationNumber
    • ActualProductionDate
    • ActualErectionDate
  • Pset_PrecastConcreteElementGeneral
    • TypeDesignation
    • CornerChamfer
    • ManufacturingToleranceClass
    • FormStrippingStrength
    • LiftingStrength
    • ReleaseStrength
    • MinimumAllowableSupportLength
    • InitialTension
    • TendonRelaxation
    • TransportationStrength
    • SupportDuringTransportDescription
    • SupportDuringTransportDocReference
    • HollowCorePlugging
    • CamberAtMidspan
    • BatterAtStart
    • BatterAtEnd
    • Twisting
    • Shortening
    • PieceMark
    • DesignLocationNumber
  • Pset_RepairOccurrence
    • RepairContent
    • RepairDate
    • MeanTimeToRepair
  • Pset_Risk
    • RiskName
    • RiskType
    • NatureOfRisk
    • RiskAssessmentMethodology
    • UnmitigatedRiskLikelihood
    • UnmitigatedRiskConsequence
    • UnmitigatedRiskSignificance
    • MitigationPlanned
    • MitigatedRiskLikelihood
    • MitigatedRiskConsequence
    • MitigatedRiskSignificance
    • MitigationProposed
    • AssociatedProduct
    • AssociatedActivity
    • AssociatedLocation
  • Pset_RoofCommon
    • Reference
    • Status
    • AcousticRating
    • IsExternal
    • ThermalTransmittance
    • FireRating
    • LoadBearing
  • Pset_ServiceLife
    • ServiceLifeDuration
    • MeanTimeBetweenFailure
  • Pset_Tolerance
    • ToleranceDescription
    • ToleranceBasis
    • OverallTolerance
    • HorizontalTolerance
    • OrthogonalTolerance
    • VerticalTolerance
    • PlanarFlatness
    • HorizontalFlatness
    • ElevationalFlatness
    • SideFlatness
    • OverallOrthogonality
    • HorizontalOrthogonality
    • OrthogonalOrthogonality
    • VerticalOrthogonality
    • OverallStraightness
    • HorizontalStraightness
    • OrthogonalStraightness
    • VerticalStraightness
  • Pset_Uncertainty
    • UncertaintyBasis
    • UncertaintyDescription
    • HorizontalUncertainty
    • LinearUncertainty
    • OrthogonalUncertainty
    • VerticalUncertainty
  • Pset_Warranty
    • WarrantyIdentifier
    • WarrantyStartDate
    • IsExtendedWarranty
    • WarrantyPeriod
    • WarrantyContent
    • PointOfContact
    • Exclusions
  • Qto_BodyGeometryValidation
    • GrossSurfaceArea
    • NetSurfaceArea
    • GrossVolume
    • NetVolume
    • SurfaceGenusBeforeFeatures
    • SurfaceGenusAfterFeatures
  • Qto_RoofBaseQuantities
    • GrossArea
    • NetArea
    • ProjectedArea

6.1.3.31.6 Concept usage

Concept Usage Description
IfcRoot (2)
IfcObjectDefinition (9)
IfcObject (5)
IfcProduct (18)
IfcElement (44)
IfcBuiltElement (3)
Click to show 81 hidden inherited concepts
IfcRoof (5)
Element Decomposition General

Geometric representation by aggregated elements

If the IfcRoof has components (referenced by SELF\IfcObject.IsDecomposedBy) then no independent geometric representation shall be defined for the IfcRoof. The IfcRoof is then geometrically represented by the geometric representation of its components. The components are accessed via SELF\IfcObject.IsDecomposedBy[1].RelatedObjects. The geometric representations that are supported for the aggregated elements are defined with each element. See geometric use definition for IfcSlab, IfcBeam, IfcColumn, IfcBuildingElementPart and other subtypes of IfcBuiltElement.

Figure 6.1.3.31.D illustrates roof placement, with an IfcRoof defining the local placement for all aggregated elements.

roof
Figure 6.1.3.31.D — Roof placement

This concept can be applied to the following resources:

  • IfcSlab - A roof may be aggregated into slabs for each face.
Object Typing General

This concept can be applied to the following resources:

Product Local Placement General

The following restriction may be imposed by view definitions or implementer agreements:

  • If the IfcRoof establishes an aggregate, then all contained elements shall be placed relative to the IfcRoof.ObjectPlacement.
Property Sets for Objects General

This concept can be applied to the following resources:

Quantity Sets General

This concept can be applied to the following resources:

Table 6.1.3.31.G

6.1.3.31.7 Formal representation

ENTITY IfcRoof
SUBTYPE OF (IfcBuiltElement);
PredefinedType : OPTIONAL IfcRoofTypeEnum;
WHERE
CorrectPredefinedType : NOT(EXISTS(PredefinedType)) OR
(PredefinedType <> IfcRoofTypeEnum.USERDEFINED) OR
((PredefinedType = IfcRoofTypeEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType));
CorrectTypeAssigned : (SIZEOF(IsTypedBy) = 0) OR
('IFC4X3_DEV_54a9de1b.IFCROOFTYPE' IN TYPEOF(SELF\IfcObject.IsTypedBy[1].RelatingType));
END_ENTITY;

6.1.3.31.8 References

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6.1.3.31.9 Changelog

6.1.3.31.9.1 IFC4

  • where rule, CorrectPredefinedType
  • where rule, CorrectTypeAssigned
  • where rule, WR1
  • attribute ShapeType name, Changed from "ShapeType" to "PredefinedType"
  • attribute ShapeType optional, Changed from "False" to "True"

6.1.3.31.9.2 IFC4.3_DEV_54a9de1b