Window / Door Rough Opening Size
The framing dimension nothing in the catalog produced: RO from the unit size by the published conventions - a window frame + 1/2 in each way (1/4-in shim per side), a prehung door SLAB + 2 in wide and 2.5 in tall (a 36 x 80 door wants a 38 x 82.5 RO - measured from the slab, not the jambs). Adds the header rough length (+ two 1.5-in jacks) and exposes the adders as overrides, because the manufacturer's stated RO governs whenever it differs.
Formula and source
Window: RO = frame outside dimension + 1/2 in each way (1/4-in shim per side). Prehung door: RO = SLAB + 2 in wide, + 2.5 in tall. Header rough length = RO width + 3 in (two 1.5-in jack studs). Adders editable.
The widely published US framing conventions for rough openings, stated as DEFAULTS - not a code section; the unit manufacturer's stated RO governs whenever it differs.
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