diff --git a/include/tadah/mlip/design_matrix/design_matrix.h b/include/tadah/mlip/design_matrix/design_matrix.h
index 2edf859903d165a2884abc7b9c0604c58f153828..5a785ec5776af082d5d4e22c609abfc2d3cbe9d8 100644
--- a/include/tadah/mlip/design_matrix/design_matrix.h
+++ b/include/tadah/mlip/design_matrix/design_matrix.h
@@ -256,6 +256,9 @@ private:
       if (force) rows+=stdb(s).natoms()*3;
     }
 
+    // Add space for augmented matrix
+    rows += cols;
+
     T.resize(rows);
     Tlabels.resize(rows);
     Phi.resize(rows,cols);