Slabs and Floors

Exporting Floors to IFC

Revit floors are often created using two separate elements: a load-bearing slab and the floor per room.

For IFC export all slabs are assigned to the IfcSlab class by default. The IFC classification however has a separate class for floors, which is called IfcCovering.

To export the floor correctly, IfcExportAs is set to IFCCovering and IfcExportType FLOORING. Alternatively, both class and type can be assigned to IFCExportAs using the syntax: IFCCovering.FLOORING (or starting with Revit 2024 simply selected in the dialog):

IFC Entities and predefined Types for floors

Modeling Slabs for IFC Export

Even though Revit allows the creation of floor/sketched ceiling geometries from separate polygons, this should be avoided as it can lead to errors in calculations. When exported to IFC, such slabs are considered independent elements and all property values are assigned to each resulting IFC object.