diff --git a/dumux/io/cubegridcreator.hh b/dumux/io/cubegridcreator.hh
index 97d547c95d6f7b29e5f456d623a035a2eacec19a..adfaba3471cf6fc69bc0bbceac2e7909db0b6bc4 100644
--- a/dumux/io/cubegridcreator.hh
+++ b/dumux/io/cubegridcreator.hh
@@ -25,6 +25,8 @@
 #ifndef DUMUX_CUBE_GRID_CREATOR_HH
 #define DUMUX_CUBE_GRID_CREATOR_HH
 
+#warning This file is deprecated and will be removed after Dumux 2.9. Use the default (Dumux::GridCreator). Structured grids can be defined via the input file now (see handbook). Set CellType = Cube for cube grid.
+
 #include <dune/grid/utility/structuredgridfactory.hh>
 
 #include <dumux/common/basicproperties.hh>
diff --git a/dumux/io/dgfgridcreator.hh b/dumux/io/dgfgridcreator.hh
index ff501a351c649c62abc5cdde1d5a5858709a3f4e..f5587457780eb18ebbd092459d72fbfb2810c5c5 100644
--- a/dumux/io/dgfgridcreator.hh
+++ b/dumux/io/dgfgridcreator.hh
@@ -23,6 +23,8 @@
 #ifndef DUMUX_DGF_GRID_CREATOR_HH
 #define DUMUX_DGF_GRID_CREATOR_HH
 
+#warning This file is deprecated and will be removed after Dumux 2.9. Use the default grid creator (Dumux::GridCreator).
+
 #include <dune/common/parallel/mpihelper.hh>
 #include <dune/grid/io/file/dgfparser.hh>
 
diff --git a/dumux/io/simplexgridcreator.hh b/dumux/io/simplexgridcreator.hh
index 092cfc6f91e8f0c8e72045b948f25e069bcdf3a4..1bf469197b9a5be19eb67c6860012c684c23a1bf 100644
--- a/dumux/io/simplexgridcreator.hh
+++ b/dumux/io/simplexgridcreator.hh
@@ -25,6 +25,8 @@
 #ifndef DUMUX_SIMPLEX_GRID_CREATOR_HH
 #define DUMUX_SIMPLEX_GRID_CREATOR_HH
 
+#warning This file is deprecated and will be removed after Dumux 2.9. Use the default (Dumux::GridCreator). Structured grids can be defined via the input file now (see handbook). Set CellType = Simplex for simplex grid.
+
 #include <dumux/common/propertysystem.hh>
 #include <dumux/common/parameters.hh>