(1) Allowable nursing home square footage is the external dimensions of the building utilized and licensed as a nursing home less all unallowable square footage as outlined in subsection (2) of this section. Allowable nursing home square footage includes the following:

(a) All necessary, ordinary, and reasonable space on the campus or adjacent to the campus utilized by the residents and staff of the nursing home including in administrative and support capacities; and

(b) Basements to the extent they are utilized for administrative or support functions including the storage of equipment and records.

(2) Unallowable nursing home square footage includes, but is not limited to:

(a) Courtyards or other areas not surrounded by four walls and a contiguous roof;

(b) Patios and decks; and

(c) Off-site storage space.

(3) Off-site administrative square footage is allowable to the extent it is:

(a) Allocated on the cost report, if appropriate;

(b) Not otherwise unallowable under subsection (2) of this section; and

(c) Used for administrative purposes.

(4) Off-site administrative square footage is allowable up to ten percent of the combined total allowable square footage. Any square footage over ten percent of the combined total allowable square footage in unallowable.

(5) In order to be allowable, all space must be identified on a site plan, blueprint, or county assessment identifying the gross external square footage.