The actual height of the stairs risers in the stairs. 
   Namespace:   Autodesk.Revit.DB.Architecture  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0) 
  Since:  2013 
Syntax
Remarks
 The stairs height is determined by its base and top elevation. So, the actual riser height = stairs height / desired riser number.