BF&K Inc., an Alabama engineer constructor firm specializing in process industries, and Tindall Concrete Products have been working together building pulp and paper facilities for five years. The two companies teamed up in order to experiment with pre-stressed concrete as an alternative to steel in mill construction. The two companies found that a hybrid structure, consisting of a precast concrete frame and operating floor and a steel roof and siding, was most effective, both in terms of durability and cost. The benefits of prestressed, precast concrete structures can be categorized into five areas: Durability, strength, design flexibility, improved scheduling and maintenance.