I found a lot about this topic, but no solutions. It's possible to create my own GDL-elements (windows, doors, toilet, etc.) with the parameter building material, then I'll got the right structur in ifc. With the right structur I mean, that the attribute Ifcmaterial is on the same position for walls, slabs, windows, etc.
In the standard-library all the elements haven't the attribute for the building materials... would be great, but are there any solutions to get an attribute at this position directly in Archicad? Otherwise we've to use simplebim and map it there.