Last year we built a nice patio attached to the back of the house. As there was very little snow last year we didn't have any problems. This year we are getting quite a lot of snow and an ice dam built up along the outer edge so Mike had to climb up and chip the ice dam off and also cleared the snow off the roof. We are thinking of running a series of heat tapes across the patio roof (which is metal) to keep the snow and ice from building up. Has anyone of you done this or heard of it done?