Figure 4. This is an annotated, revised, and schematic version of the section through E. Sibley Hall provided in the Assessment Report prepared by Ryan-Biggs Associates in May 2009. The black lines show an idealized condition, with no displacement of columns, walls, or girders; the red lines and tones show the current condition (not to scale), with a small outward displacement of the exterior masonry wall (mentioned in the Assessment report, but not visible to the unaided eye), a large inward displacement of the interior wooden columns and their steel girders, and a substantial rotation and displacement of the wooden attic joists and rafters that are supported by the displaced columns/girders on one side, and by the inclined Mansard structure on the other side; and the blue dotted lines show a possible failure mechanism. The roof structure appears to be unstable in its current configuration. (Annotations and revisions by J. Ochshorn, April 2018)