diff --git a/dune/matrix-vector/genericvectortools.hh b/dune/matrix-vector/genericvectortools.hh
index 50744db7b86f160c8deda04a19958f40686ea445..8cafcb433ad738435f4cde74944cc29b9b3cb18f 100644
--- a/dune/matrix-vector/genericvectortools.hh
+++ b/dune/matrix-vector/genericvectortools.hh
@@ -65,7 +65,7 @@ struct Helper<Scalar, typename std::enable_if_t<IsNumber<Scalar>::value>> {
 
   static void readBinary(std::istream& s, Scalar& v) {
     for(auto&& vi: v)
-      s.read(reinterpret_cast<char*>(&v), sizeof(Field));
+      s.read(reinterpret_cast<char*>(&v), sizeof(Scalar));
   }
 
   template <class BitVector>