Not exactly a "ridge" cap, because I have a shed roof on my little cabin, but the cap at the top of the slope. Lockseam metal roof ("Duratech"), 12" panels. The dealer (I assume on manufacturer's recommendation) has supplied 1" x 1" polyurethane foam w/ adhesive back to put under cap, to keep water from blowing up under. Somehow I don't think this stuff will last nearly as long as the roof. Wondering what roofing people think and are using.