TAMLYN ATTIC VENTILATION CALCULATOR
Note: Calculations are based on 1 square foot of Net Free Area
for every 150 square feet of attic floor space.

 

More Attic ventilation improves indoor air quality and Moisture Management

 

SELECT THE ROOF PITCH THAT IS CLOSEST TO YOURS

ROOF PITCH :Up to 6/12 7/12 to 10/12 11/12 and Up
To Determine Your Roof Pitch : Place a level against the roof as shown. From the point where the level touches the roof, measure out 12 inches. From this point measure the distance in inches from the bottom of the level to the roof. This will be the first number in the roof pitch. the second number will always be 12.
Enter the width and length of your home, including overhang (in feet):
WIDTH :   Ft  
LENGTH :   Ft  
ATTIC SIZE :   Sq. Ft.

Read Intake Vents and Exhaust Vents needed at specific Roof Pitch. Numbers are expressed as Linear Feet.

 

INTAKE VENTS

 

SNAPVENT® / EZVENT® - 9 sq.in./foot NFA Continuous Soffit Intake Vents

Linear Ft. 

You need  8' pieces or 12' pieces

For attics greater than 3500 sq.ft. we recommend a minimum of 12.7 NFA per foot

 or

SNAPVENT® WIDE / HAT SHAPED VENT WIDE - 12.7 sq.in./foot NFA

Linear Ft.

You need  8' pieces

12.7 sq.in./foot NFA Continuous Soffit Intake Vents for 0 lot line

 

 

EXHAUST VENTS

 

RIDGE VENTS (EXHAUST) - 18 sq.in./foot NFA Ridge Vents with Baffle System
Linear Ft. You need  4' pieces

or

         TSB150 (EXHAUST) - 150 NFA total each Vents
Number of vents required

 
 

 

We recommend running ridge vent and soffit vents continuously in all available horizontal areas for best aesthetics and air flow.

 

Remember if you don't have enough roof peek to meet the required exhaust venting you can add The TSB150 static vent to get to the required NFA.  TSB150 provides 150 NFA each. 150* square inches of net free area = 8.3’ of Ridge Vent

© R. H. Tamlyn & Sons, LP.