I recently bought a house with cement roofing tiles. They are about 1 ft sq. each. The roof may be 60-70 years old, in a midwest climate. My first question, is can I determine what kind they are....ie. asbestos fiber cement...etc.? Is it possible to clean the tiles? Is it possible to seal the tiles? Should I avoid walking on the tiles? I have been told the roof needs replaced soon. Is it possible to replace the decking, and reuse the tiles? If I do have to replace the roof, is there any hazardous considerations for asbestos fiber concrete tile disposal?