Home » roofing-bars » How does a roofing bar work? How does a roofing bar work? Chris 17th March 2020 How does a roofing bar work? Shop for Roofing Bars A roofing bar works through the action of the user opening and closing the handle. This controls the jaws which clamp securely around the batten. The roofing bar holds the batten firmly in place whilst the user fixes it to the roof.