Siding problems. Units with either “Missing bricks, siding, or other outside wall material” or “Sloping outside walls” were classified as having Siding Problems. “Missing bricks, siding, or other outside wall material” applies to the exterior wall (including chimney) of the structure. Those defects may have been caused by storm, fire, flood, extensive neglect, vandalism and so forth. Materials may include clapboard siding, shingles, boards, brick, concrete, and stucco. The missing materials do not necessarily expose the interior of the unit directly to weather. Missing materials resulting from construction activity were not included unless construction had been abandoned. “Sloping outside walls” is a critical defect indicating continuous neglect or serious damage to the structure. Only walls with substantial sagging were included.