This calculator is designed specifically for Master Flash® products. Using this calculator in association with foreign or competitive products may result in installation failure. This Calculator is designed to provide assistance in planning only. It is to be used as a guide and not the ultimate source of information. Every effort has been made to make this as complete and accurate as possible. If you are installing on pitches greater than 10/12 or you desire further information, please call Aztec Washer: 1-800-WASHER-5