(a) If, on the basis of the facts presented at a hearing on a petition for a variance, the board of adjustment determines that there are great practical difficulties or unnecessary hardships in the manner of applying the strict letter of any land-use regulation on the land of the petitioner, the board shall record that determination and make and record findings of fact as to the specific conditions that establish the difficulties or hardships.
(b) On the basis of the board’s determinations and findings under Subsection (a) of this section, the board of adjustment by order may authorize a variance from the land-use regulations that will:
(1) relieve the great practical difficulties or unnecessary hardships;
(2) not be contrary to the public interest;
(3) observe the spirit of the land-use regulations;
(4) secure the public health, safety, and welfare; and
(5) do substantial justice.