Converting flat roof garage (built up hot asphalt/felt layers on 3/4" plywood deck) to 4/12 pitch. Need to remove flat roof's rake to extend flat roof's sheathing up to the added new gable. Need advice re best tooth choice since I'll be cutting roughly a 1" thickness of mopped asphalt-felt, insulation, plywood and the occasional nails. I experimented with a circular saw, to no avail. (Chose it first for ease in controlling depth and direction of cut.) The asphalt migrates into the saw's guard, spindle, etc. resulting in a clogged up mess. I optimistically hope the reciprocating saw will work better, hence the blade tooth info request. But if some one has other suggestions, please be my guest.