Planning reference only — no interactive calculator is available on this page.
A ventilation assessment starts with the building configuration, applicable requirements and the installed vents. This guide lists information to gather for that review.
Planning Information:
Information to gather for a professional assessment:
- Total attic or roof deck area
- Roof slope or pitch
- Current intake and exhaust vent types
- Climate zone or building location
- Type of insulation or vapor barrier used
This page does not calculate ventilation requirements. Net free ventilating area (square inches) and airflow (CFM) are different quantities; this guide provides no conversion or recommended intake/exhaust values.
When This Guide May Help:
- Planning a new roofing system or retrofit
- Addressing indoor humidity or attic heat issues
- Ensuring compliance with local building codes
- Evaluating existing ventilation systems for performance gaps
Want a professional review of your roof’s ventilation system? Schedule a RAC assessment and keep your roof breathing right.