We are wanting to remove two walls boxing our kitchen in. We had a structural engineer out to determine if the walls could be removed. He determined that they were non load bearing and told us that could be. However when we got his written report, he said even though they were non load bearing we still had to put 4x4 beams in the ceiling where the walls used to be... one of them bolted to the stresses. Why would we need to do this if the walls aren't load bearing?