Confusion about window sill terms and flashing
(1) What do you call the 2×4 piece of lumber that forms the bottom of the rough opening for a window? Is that the “window sill” or the “window sill plate”, or is it the same thing (or is it something else)?
(2) Are windows supposed to come with separate window sills? This article refers to, “a sloped secondary sill tucked under the sill that comes with the window…” What is the sill that comes with the window? Is it part of the window or a separate piece? I’m pretty sure my brand-name nail-fin window didn’t come with extra, uninstalled pieces.
(3) What is the piece under the window in this diagram? It’s not labeled. I presume it is what I think is called “sill pan flashing”. Incidentally, the diagram is labeled “Bird’s Eye View” but it seems to be a side view.
(4) Are rigid pan flashings still recommended? This article recommends sill pan flashing (which I presume means a rigid flashing), but a Builder Online article claims that “Flexible peel and stick flashing membranes have made rigid pre-formed pan flashings a thing of the past.”