About 12 years ago I used double coverage roll roofing on two new portions of my house: a large shed dormer, slope about 3 in 12, facing north and subject to heavy wind at times. Also a porch roof, slope one half in twelve, that I occasionally walk on to hoist things to the second floor. The roll roofing is looking pretty sad and a few sections have broken off. What is the best replacement material for these applications? I expect to use a contractor this time.