diff --git a/src/thermophysicalModels/basic/basicThermo/basicThermo.H b/src/thermophysicalModels/basic/basicThermo/basicThermo.H
index 4b91a3adc8..92be7a6008 100644
--- a/src/thermophysicalModels/basic/basicThermo/basicThermo.H
+++ b/src/thermophysicalModels/basic/basicThermo/basicThermo.H
@@ -182,7 +182,7 @@ public:
             const word& phaseName
         )
         {
-            return name + phaseName;
+            return IOobject::groupName(name, phaseName);
         }
 
         word phasePropertyName(const word& name) const