
Quoting
Tennessee Code, Sec. 36-5-101(f)(1)
(f) (1) Any order for child support shall be a judgment entitled to be enforced as any other judgment of a court of this state, and shall be entitled to full faith and credit in this state and in any other state. Such judgment shall not be subject to modification as to any time period or any amounts due prior to the date that an action for modification is filed and notice of the action has been mailed to the last known address of the opposing parties. If the full amount of child support is not paid by the date when the ordered support is due, the unpaid amount is in arrears, shall become a judgment for the unpaid amounts, and shall accrue interest from the date of the arrearage, at the rate of twelve percent (12%) per year. All interest that accumulates on arrearages shall be considered child support. Computation of interest shall not be the responsibility of the clerk.