Window sizes?
Answers: For rough frame opening be sure to increase dimensions to allow for drywall, wood sill, etc. If you are using vinyl or aluminium window, add 1 1/4" to the size, and 1 1/2" to the height. Wood frame window are more precise. Check with windowpane manufacturer. All windowpane manufacturers sizes differ slightly. Either draw from them to come in and guess the rough opening sizes or, within your case (assuming not too tons windows), order the window and the manufacturer will tolerate you know their size standards. Then frame the rough openings as I described above.
I enjoy done a good bit of work on houses surrounded by most of the crafts. The one thing that I enjoy learned give or take a few windows and their sizes is that in that is no standard size. If you went to 3 different building supply stores and looked at a dozen window in respectively store you would probably find at least 50% of the window were a different size. For the rough pipe I would allow at least one inch more of a exit.
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