diff --git a/dumux/porousmediumflow/compositional/switchableprimaryvariables.hh b/dumux/porousmediumflow/compositional/switchableprimaryvariables.hh
index 57a87aefa8618c3981baf4c23cb170a97b5a4384..9e4067b0a72f4547e7a4670a81e53f5a3b0ad74e 100644
--- a/dumux/porousmediumflow/compositional/switchableprimaryvariables.hh
+++ b/dumux/porousmediumflow/compositional/switchableprimaryvariables.hh
@@ -25,6 +25,7 @@
 #ifndef DUMUX_SWITCHABLE_PRIMARY_VARIABLES_HH
 #define DUMUX_SWITCHABLE_PRIMARY_VARIABLES_HH
 
+#include <dune/common/ftraits.hh>
 #include <dune/common/exceptions.hh>
 #include <dumux/common/numeqvector.hh>
 
@@ -87,4 +88,14 @@ struct NumEqVectorTraits<SwitchablePrimaryVariables<PrimaryVariables, StateType>
 
 } // end namespace Dumux
 
+// specialize field traits for this type
+namespace Dune {
+
+template <class PrimaryVariables, class StateType>
+struct FieldTraits<Dumux::SwitchablePrimaryVariables<PrimaryVariables, StateType>>
+: public FieldTraits<PrimaryVariables>
+{};
+
+} // end namespace Dune
+
 #endif