Final answer:
The building code typically specifies that stairways with solid risers must have a nosing that is at least ¾-inch but not more than 1¼ inches to ensure safety and accessibility.
Step-by-step explanation:
The question relates to the construction specifications for stairways, specifically the dimensions of the nosing, which is the part of the tread that overhangs the riser beneath. The required size for a nosing ensures safety and accessibility on stairways. In accordance with most building codes, a nosing not less than ¾ inch but not more than 1¼ inches should be provided on stairways with solid risers. This range allows for enough overhang to protect the edge of the step and provide a lip for better footing, but not so much that it becomes a tripping hazard.