diff --git a/dune/gfe/tensorssd.hh b/dune/gfe/tensorssd.hh
index 43680fe5e7283f00ba434c1a59de2b9cda2893e4..ac83b94ce4d57e7721b1e6bed113f62101043eca 100644
--- a/dune/gfe/tensorssd.hh
+++ b/dune/gfe/tensorssd.hh
@@ -8,7 +8,8 @@
 #include <array>
 
 #include <dune/common/fmatrix.hh>
-    
+#include <dune/istl/matrix.hh>
+
 /** \brief A third-rank tensor with two static (SS) and one dynamic (D) dimension
  * 
  * \tparam T Type of the entries