The weather looks great, so I'll be starting my re-roof this Thursday. I have a couple more questions (do they ever really end?).
1) In several online forums I have seen reference to applying I&W around pipe projections. When I picture this in my head it doesn't seem like it would add protection if it was applied to the roof deck, cause if there is water on the deck, under the felt, it's going to get through whether there is a pipe there or not. The only way I can see it adding protection is if I put a strip of ice and water on the edges of the pipe flashing and then overlapped another strip on the top, covering the side strips and sealing the top of the flashing to the felt. This way, if there is water on the felt, it can't get under the flashing, the I&W would direct it to the top of the flashing and then back out onto the shingles. But this seems clunky, and messy and would make for a real PITA if the flashing needed to be replaced. When I&W is applied around pipes, how and why is it done?
2) Fastening valley metal. I will be applying 24" valley metal (per Oregon residential code and shingle manufacturer specification manual) to two 19 foot valleys on my roof. The roofing supply company I have ordered from recommended two nails at the top corners, 1" in from top and side edge, and two nails halfway down, 1" in from the edge. The shingle manufacturers instructions (Malarkey), specify fastening the valley metal down every 10-12 inches, they also recommend fastening shingles through the metal up to 6" from valley center. When browsing contractor and roofers forums, I see many who fasten the metal, many who chastise it and many who simply say "follow the shingle manufacturers instructions". What are your thoughts on this?
I know I asked about fastening the valley metal before, and I thank Tinner for the replies to that thread, but I am hoping to get thoughts on this from more of you. It is interesting to me that there is such massively divergent information on this.