Duro-Last Roofing Inc., Saginaw, Mich., offers Duro-Shield roofing for metal retrofit. The prefabricated, single-ply system can be installed right over an existing metal roof without an expensive tear-off. It is a cost-effective, long-term way to protect buildings against rain, temperature changes, interior drips, ice build-up, and rust and corrosion. Contractors who install the Duro-Shield system have fewer hassles on the rooftop, meaning less time spent on the job and lower installation costs.