Before purchasing metal roofing materials for installation, measure the roof from multiple angles to determine how much material to buy. To achieve optimal results, tear the existing roofing off before installing the metal, and practice installing the metal on a sample frame before installing the roof. Square the first panel to ensure the remaining panels are even. When using chalk lines to square the panel, opt for blue chalk, as it's easier to remove than other colors.
After tearing off the old roofing, replace rotted boards before installing the metal roofing panels. Install the underlayment appropriate for the region by layering the traditional kind with water-and-ice underlayment. Allow the underlayment to overlap by up to 6 inches.
Install the drip edge, metal flashing and trim before installing the panels. To easily cut the metal panels, score each panel with a box cutter, and bend the panel back and forth until it breaks. To attach the metal to the drip edge, cut each panel to create a 1-inch bend, and attach the panels to the drip edge with screws.
Avoid over-tightening the screws. After the panels are installed, sweep the roof to remove metal shavings, as these cause rust spots. To avoid accidents, wear non-slip shoes with rubber soles, and use safety equipment such as a harness while working on the roof.