Hello people. I will be doing my fathers' roof and having never done one I boned up with this site. In the how to section at this site it showed how to do flash and shingle a valley (a verticle valley) 18" of mineral roll, metal flashing, and then 36" of mineral roll over that. Well my fathers roof has a horizontal valley ( regular roof peak and then runs into an almost flat roof) Shold I use the same techniqe as a vertical valley, also, sorry to go long, but is flashing when you buy it already contoured or pre-formed or do you simply bend it into the valley. If its preformed I'm not sure how to figure the angle 45 0 etc so hopefully its bendable. If you use those waterproof membranes that stick on, does that change how you would flash the valley. I figure it would just be extra protection. We are only replacing the slightly angled flat part of the roof as that is where it leaks. We will go up with several courses of shingles and tie into the old. Well thank you if you read this far.

 

Metal flashing (galvanized and aluminum) comes in rolls of various widths.
It will unroll flat and you just bend it to match the angle.
I don't think that stickon membranes would help in this situation.
You might want to use black plastic roofing cement on the bare roofing seam where the two roofs meet as leak insurance, before layering the roll roofing and flashing.
Good Luck!

 

Thanks Old Guy. I'll keep that in mind