Measurement Guide

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How to Measure Your Rough Opening
1. If you are measuring for a new construction, skip to Step 6.
2. If you are replacing an existing door, remove the casing or trim
from one side of the door open.
3. Measure the width of the outside of the jamb in 3 places: top,
center and bottom. Record the smallest of the measurements
4. Measure the height of the outside of the frame from the floor in 2
places: left and right. Record the smallest of the measurements
5. This width and height will be your door’s unit dimension
6. Measure the width of the opening from stud to stud in 3 places:
top, center and bottom. Record the smallest of the measurements
7. Measure the height of the opening from stud to floor in 2 places:
left and right. Record the smallest of the measurements
8. This width and height will be your rough opening
9. Measure the wall thickness, this is the width of the studs. 2”x4” or
2”x6” studs are most commonly used.
a. 2”x4” = 4-9/16” jamb, 2”x6” = 6-9/16” jamb