In case the value of the premises is, in the opinion of the commissioners, more than $15,000, and cannot be divided as is provided for in Section 12-910 of this Act, they shall make and sign an appraisal of the value thereof, and deliver the same to the officer, who shall deliver a copy thereof to the judgment debtor, or to some one of the family of the age of 13 years or upwards, with a notice thereto attached that unless the judgment debtor pays to such officer the surplus over and above $15,000 on the amount due on the judgment within 60 days thereafter, such premises will be sold.