Construction
Door Rough Opening Calculator
Pre-hung door size to rough opening width by height.
Rough opening
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- RO width
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- RO height
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- Header size (typical)
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FAQ
Why add 2 inches? +
You need about 1/2 inch shim space on each side and clearance above to plumb and shim the jamb square.
What size header? +
For load-bearing walls: 2-2x6 up to 3 ft span, 2-2x8 up to 5 ft, 2-2x10 up to 7 ft.