Bossman! thanks for the question. Metal roofs are known for their exceptional warranties, often boasting a 50-year no-leak guarantee in Ontario. However, these warranties come with a caveat: you must strictly adhere to the manufacturer's specifications. For instance, if they require Grace Ice & Water Shield for the underlay, you must comply. That said, there are many alternative products that are more affordable and perform just as well as Grace. I would steer clear of Titanium UDL 30, as there are superior options available, such as Laplock PSU or even UDL 50.