diff --git a/src/regionModels/surfaceFilmModels/thermoSingleLayer/thermoSingleLayer.C b/src/regionModels/surfaceFilmModels/thermoSingleLayer/thermoSingleLayer.C
index 91c1a6997a..9f08a2a886 100644
--- a/src/regionModels/surfaceFilmModels/thermoSingleLayer/thermoSingleLayer.C
+++ b/src/regionModels/surfaceFilmModels/thermoSingleLayer/thermoSingleLayer.C
@@ -29,11 +29,12 @@ License
 #include "fvcLaplacian.H"
 #include "fvcFlux.H"
 #include "fvm.H"
-#include "addToRunTimeSelectionTable.H"
 #include "zeroGradientFvPatchFields.H"
+#include "mixedFvPatchFields.H"
 #include "mappedFieldFvPatchField.H"
 #include "mapDistribute.H"
 #include "constants.H"
+#include "addToRunTimeSelectionTable.H"
 
 // Sub-models
 #include "filmThermoModel.H"
@@ -67,7 +68,8 @@ wordList thermoSingleLayer::hsBoundaryTypes()
         if
         (
             T_.boundaryField()[patchi].fixesValue()
-         || bTypes[patchi] == mappedFieldFvPatchField<scalar>::typeName
+         || isA<mixedFvPatchScalarField>(T_.boundaryField()[patchi])
+         || isA<mappedFieldFvPatchField<scalar>>(T_.boundaryField()[patchi])
         )
         {
             bTypes[patchi] = fixedValueFvPatchField<scalar>::typeName;