RoofCat OS · Field Engineering
Specialized Trade Tool Pack
High-precision field engineering calculators built for roofing contractors.
RoofCat Field Engineering
Attic Ventilation NFA Calculator
Calculated requirement
1,440 sq in NFA
Required intake
720 sq in
Required exhaust
720 sq in
Equipment conversion
Vent product / rated NFARequired
Continuous ridge vent18 sq in / linear ft40 linear ft
Box vents / slant backs50 sq in / unit15 units
Continuous soffit vents9 sq in / linear ft80 linear ft
Balanced airflow target met
Specified intake meets or exceeds exhaust capacity. Confirm each product’s listed NFA before installation.
FIELD CALCULATION AID — Always verify local municipal building code requirements.