Model "W6" Soffit
Requirements Calculator
(Soffit "W3" Calculator, Soffit "W10" Calculator)
Based on the 1/150 or 1/300 Rule
(see Building Codes for more info)

To determine how many vents of a given length (inches)
are required to properly ventilate an attic space:
soffit vents SV-W6-L28
Material Width=6"
Overall Length=28"
Free Air Space=90 sq. in.
SV-W6-L20
Material Width=6"
Overall Length=20"
Free Air Space=60 sq. in.
SV-W6-L12
Material Width=6"
Overall Length=12"
Free Air Space=30 sq. in.

Enter the length of
the building in feet
Enter the width of
the building in feet
Choose the desired vent




vents required - 1/300 rule



vents required - 1/150 rule

Enter the total area of attic
in square feet



Choose the desired vent




vents required - 1/300 rule



vents required - 1/150 rule
OR

Application: One vent for intake per:
Model
Sq. Feet
of Floor
1/150
Sq. Feet
of Floor
1/300
Net Free
Vent Area
in Sq. Inches
Net Free
Vent Area
in Sq. Feet
SV-W6-L12
63
126
30
0.21
SV-W6-L20
126
252
60
0.42
SV-W6-L28
186
372
90
0.62

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