Frame size is not clear opening

Sash, frame and hardware reduce the usable opening. Use documented net clear dimensions for the exact unit instead of assuming the rough opening qualifies.

Measure sill height and grade

Record the finished floor, finished sill, exterior grade and any window-well dimensions. These conditions affect the complete escape path.

Choose operation intentionally

Casements can provide a large clear opening relative to frame size, but handing, hardware, screens and well clearance must work together.

Confirm locally

Requirements can depend on building type, room use, existing conditions and local rules. The project authority should confirm the accepted solution.

Turn the guide into a real opening schedule.

Keep every dimension, option, pressure, document, and delivery note connected to the same opening ID.

Start the configuration

Questions about this topic

Can an existing small basement opening become egress without masonry work?

Sometimes a qualifying unit fits, but many openings require enlargement or a different well. Verify the required clear opening and site condition before choosing a window.