What are these wall materials with 0 sq. m. area which sometimes appear in the building element report and sometimes cause a "too many walls and doors" error? Helen Reich July 27, 2017 13:11 Follow These are usually caused by stacked nodes. See also: How do stacked nodes happen? How can stacked nodes can be located? What impact do stacked nodes have on a rating and its accuracy? How can stacked nodes can be removed (without redrawing zones - that creates other problems like identifying zones connected by stairs)? Have more questions? Submit a request 0 Comments Please sign in to leave a comment.