diff --git a/dune/gfe/cosseratvtkwriter.hh b/dune/gfe/cosseratvtkwriter.hh
index f693a3c7f010765010a4ee5de7d5179aa4a1bda8..abe48b260d2b9bc6d8fb6839c644d0d8d4441261 100644
--- a/dune/gfe/cosseratvtkwriter.hh
+++ b/dune/gfe/cosseratvtkwriter.hh
@@ -178,8 +178,7 @@ public:
           else
             DUNE_THROW(Dune::IOError, "Unsupported element type '" << nE.first << "' found!");
         }
-        std::vector<int> connectivity(connectivitySize);
-
+        std::vector<unsigned int> connectivity(connectivitySize);
 
         size_t i=0;
         for (const auto& element : elements(gridView, Dune::Partitions::interior))
diff --git a/dune/gfe/vtkfile.hh b/dune/gfe/vtkfile.hh
index cf14e8ef653547c5f879bcf459f138c3cf5707e6..eee618581f8277b626755b0527b4ec3f9a156d51 100644
--- a/dune/gfe/vtkfile.hh
+++ b/dune/gfe/vtkfile.hh
@@ -346,7 +346,7 @@ namespace Dune {
 
       std::vector<Dune::FieldVector<double,3> > points_;
 
-      std::vector<int> cellConnectivity_;
+      std::vector<unsigned int> cellConnectivity_;
 
       std::vector<int> cellOffsets_;