I’m laying an Indian sandstone patio but the steps are uneven and not parallel as well as having a big step down from the French doors. The plan is to lay slabs on top and render the side and front faces but is it possible to first add more concrete to extend the bottom step to make them all even? It would only be by a few inches but was worried this might not adhere properly to the existing stuff. If not I could lay extra bricks attached to them but assume this might have the same problem with breaking off in time. Any help would be appreciated

