diff --git a/dumux/common/pdesolver.hh b/dumux/common/pdesolver.hh
index 12ae1f9dd130c927a879f2510590a8e824f83dfb..e06c5cc4c9ffd6dd1456e1e54a3ffaee71227fa4 100644
--- a/dumux/common/pdesolver.hh
+++ b/dumux/common/pdesolver.hh
@@ -26,6 +26,7 @@
 
 #include <memory>
 
+#include <dumux/common/typetraits/matrix.hh>
 #include <dumux/common/timeloop.hh>
 
 namespace Dumux {
@@ -101,6 +102,29 @@ protected:
     LinearSolver& linearSolver()
     { return *linearSolver_; }
 
+    /*!
+     * \brief Helper function to assure the MultiTypeBlockMatrix's sub-blocks have the correct sizes.
+     */
+    template<class M>
+    bool checkSizesOfSubMatrices(const M& A) const
+    {
+        static_assert(isMultiTypeBlockMatrix<M>::value, "This function can only be used with MultiTypeBlockMatrix");
+        bool matrixHasCorrectSize = true;
+        using namespace Dune::Hybrid;
+        using namespace Dune::Indices;
+        forEach(A, [&matrixHasCorrectSize](const auto& rowOfMultiTypeBlockMatrix)
+        {
+            const auto numRowsLeftMostBlock = rowOfMultiTypeBlockMatrix[_0].N();
+
+            forEach(rowOfMultiTypeBlockMatrix, [&matrixHasCorrectSize, &numRowsLeftMostBlock](const auto& subBlock)
+            {
+                if (subBlock.N() != numRowsLeftMostBlock)
+                    matrixHasCorrectSize = false;
+            });
+        });
+        return matrixHasCorrectSize;
+    }
+
 private:
     std::shared_ptr<Assembler> assembler_;
     std::shared_ptr<LinearSolver> linearSolver_;
diff --git a/dumux/linear/pdesolver.hh b/dumux/linear/pdesolver.hh
index 8214d01ed689ca00162f3b0eaa49e02583e79678..dca3534564750aef506958e9e40d5404ccaa2ca3 100644
--- a/dumux/linear/pdesolver.hh
+++ b/dumux/linear/pdesolver.hh
@@ -269,8 +269,7 @@ private:
                            SolutionVector& x,
                            SolutionVector& b)
     {
-        // check matrix sizes
-        assert(checkMatrix_(A) && "Sub blocks of MultiType matrix have wrong sizes!");
+        assert(this->checkSizesOfSubMatrices(A) && "Sub-blocks of MultiTypeBlockMatrix have wrong sizes!");
 
         // TODO: automatically derive the precondBlockLevel
         return ls.template solve</*precondBlockLevel=*/2>(A, x, b);
@@ -294,8 +293,7 @@ private:
                            SolutionVector& x,
                            SolutionVector& b)
     {
-        // check matrix sizes
-        assert(checkMatrix_(A) && "Sub blocks of MultiType matrix have wrong sizes!");
+        assert(this->checkSizesOfSubMatrices(A) && "Sub-blocks of MultiTypeBlockMatrix have wrong sizes!");
 
         // create the bcrs matrix the IterativeSolver backend can handle
         const auto M = MatrixConverter<JacobianMatrix>::multiTypeToBCRSMatrix(A);
@@ -323,27 +321,6 @@ private:
         return converged;
     }
 
-    //! helper method to assure the MultiType matrix's sub blocks have the correct sizes
-    template<class M = JacobianMatrix>
-    typename std::enable_if_t<!isBCRSMatrix<M>(), bool>
-    checkMatrix_(const JacobianMatrix& A)
-    {
-        bool matrixHasCorrectSize = true;
-        using namespace Dune::Hybrid;
-        using namespace Dune::Indices;
-        forEach(A, [&matrixHasCorrectSize](const auto& rowOfMultiTypeMatrix)
-        {
-            const auto numRowsLeftMostBlock = rowOfMultiTypeMatrix[_0].N();
-
-            forEach(rowOfMultiTypeMatrix, [&matrixHasCorrectSize, &numRowsLeftMostBlock](const auto& subBlock)
-            {
-                if (subBlock.N() != numRowsLeftMostBlock)
-                    matrixHasCorrectSize = false;
-            });
-        });
-        return matrixHasCorrectSize;
-    }
-
     //! initialize the parameters by reading from the parameter tree
     void initParams_(const std::string& group = "")
     {
diff --git a/dumux/nonlinear/newtonsolver.hh b/dumux/nonlinear/newtonsolver.hh
index e938fdb372ec47154d205f8b5dd6d356f30a07cb..4d3c0f24468fa4e9e65fc95cfba71f7877239f7e 100644
--- a/dumux/nonlinear/newtonsolver.hh
+++ b/dumux/nonlinear/newtonsolver.hh
@@ -1095,8 +1095,7 @@ private:
                            SolutionVector& x,
                            SolutionVector& b)
     {
-        // check matrix sizes
-        assert(checkMatrix_(A) && "Sub blocks of MultiType matrix have wrong sizes!");
+        assert(this->checkSizesOfSubMatrices(A) && "Sub-blocks of MultiTypeBlockMatrix have wrong sizes!");
 
         // TODO: automatically derive the precondBlockLevel
         return ls.template solve</*precondBlockLevel=*/2>(A, x, b);
@@ -1120,8 +1119,7 @@ private:
                            SolutionVector& x,
                            SolutionVector& b)
     {
-        // check matrix sizes
-        assert(checkMatrix_(A) && "Sub blocks of MultiType matrix have wrong sizes!");
+        assert(this->checkSizesOfSubMatrices(A) && "Sub-blocks of MultiTypeBlockMatrix have wrong sizes!");
 
         // create the bcrs matrix the IterativeSolver backend can handle
         const auto M = MatrixConverter<JacobianMatrix>::multiTypeToBCRSMatrix(A);
@@ -1149,27 +1147,6 @@ private:
         return converged;
     }
 
-    //! helper method to assure the MultiType matrix's sub blocks have the correct sizes
-    template<class M = JacobianMatrix>
-    typename std::enable_if_t<!isBCRSMatrix<M>(), bool>
-    checkMatrix_(const JacobianMatrix& A)
-    {
-        bool matrixHasCorrectSize = true;
-        using namespace Dune::Hybrid;
-        using namespace Dune::Indices;
-        forEach(A, [&matrixHasCorrectSize](const auto& rowOfMultiTypeMatrix)
-        {
-            const auto numRowsLeftMostBlock = rowOfMultiTypeMatrix[_0].N();
-
-            forEach(rowOfMultiTypeMatrix, [&matrixHasCorrectSize, &numRowsLeftMostBlock](const auto& subBlock)
-            {
-                if (subBlock.N() != numRowsLeftMostBlock)
-                    matrixHasCorrectSize = false;
-            });
-        });
-        return matrixHasCorrectSize;
-    }
-
     //! initialize the parameters by reading from the parameter tree
     void initParams_(const std::string& group = "")
     {