Window Rough Opening Size with Beveled Siding
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This is a basic question but I’m not really finding a straight answer anywhere . I am going to be framing out windows and using beveled pine siding to create a sloped sill. Everything I’ve read says to add 3/8 to 1/2in to the rough opening to account for the beveled siding. So if I plan to do a rough opening of 1/2in on top and bottom (1in total) would I add an additional 3/8in to that? So the RO would be a total of 1 3/8”? That seems kind of big. Maybe I am over thinking this.
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Replies
It depends on the window, but for typical North American-style windows I usually see 1/4" on all sides recommended for rough openings. If you go much larger than the manufacturer recommends, nails in the nailing fins can be too close to the edge of the framing.
If you have European-style windows, those usually have 1/2" gaps on all sides.
Clapboards are usually around 7/16" thick on the butt ends but that varies as well. Whatever thickness the clapboard you are using is, add that to your rough opening height.