(765 ILCS 605/23) (from Ch. 30, par. 323)

Sec. 23.

Encroachments).

If any portion of the common elements
encroaches upon any unit, or if any unit encroaches upon any portion
of the common elements or any other unit as a result of the construction,
repair, reconstruction, settlement or shifting of any building, a valid
mutual easement shall exist in favor of the owners of the common elements
and the respective unit owners involved to the extent of the encroachment.
A valid easement shall not exist in favor of any owner who creates
an encroachment by his intentional, wilful or negligent conduct or
that  of his agent.

(Source: P.A. 80-1115.)