cutting opening in hot mop roof
I would like recommendations on best way to cut an access opening in my roof about 2 foot x 4 foot. Original roofing and one replacement add to about 1 1/2 inches total dense black tarry/felty/papery stuff. This does not include underlying wood deck. I would like to use skill saw so that I can cut through roofing and wood deck separately. If I do, what would be the ideal blade to use. I realize it may not be of much use once I'm done. Are there other ways besides using skill saw. I made a small access opening from the bottom using a reciprocating saw - a miserable job. Thankfully the big opening will be from the top.