Mellon Bank agreed to buy a home finance unit.

Mellon Financial Services, a subsidiary of the Pittsburgh-based bank holding company, said it would acquire Avco Financial Services’ diversified sales division, which finances modular and prefabricated residential housing. Terms weren’t disclosed. In addition, Mellon Financial Services agreed to assume the leases of six Avco offices located in Birmingham, Ala.; Denver; Atlanta; Jackson, Miss.; Charlotte, N.C., and Austin, Tex. The offices are primarily involved in home financing. The transactions require federal regulatory approval.