Which window sizing designation is listed first in the sizing sequence?

Which window sizing designation is listed first in the sizing sequence?

• A. Rough Opening
• B. Frame Height
• C. Glass Width Size
• D. Frame Width

Answer: (C)

The starting point when sizing a window is the width of the glass. In manufacturing and ordering, the glazing pane is the fixed element around which the rest of the unit is built, so the Glass Width Size is defined first. Once the glass size is set, the frame dimensions are determined to enclose that glass with the proper clearances for glazing beads, spacers, and hardware, and the rough opening is sized to accept the finished unit with the required installation clearance. That’s why the glass width comes first in the sizing sequence—the other dimensions are derived from or adjusted to fit around that fixed glass size.

The starting point when sizing a window is the width of the glass. In manufacturing and ordering, the glazing pane is the fixed element around which the rest of the unit is built, so the Glass Width Size is defined first. Once the glass size is set, the frame dimensions are determined to enclose that glass with the proper clearances for glazing beads, spacers, and hardware, and the rough opening is sized to accept the finished unit with the required installation clearance. That’s why the glass width comes first in the sizing sequence—the other dimensions are derived from or adjusted to fit around that fixed glass size.