Hello, I live in a semidetached house, the valley between the 2 houses faces north. In winter there is always an ice dam there, I added attic insulation, roof ventilation - soffit vents and a wind turbine- but nothing helps. This winter after a snow storm we had a about 15 mm rain and the roof started to leak, along the wall in between the houses. I assume the valley is leaking. 2 questions: 1. Any suggestions regarding the ice dam ? Would a metal valley help ? 2. What option to repair the valley I have ? Thanks much, Frank