Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems.
Required residential roof vents.
Before we explore how to ventilate an attic space it is prudent to understand how much ventilation is needed.
Code requirements the international building code.
Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space.
The following are the requirements taken directly from the irc.
Soffit vents are one of the most popular intake vent styles.
The majority of the requirements related to attic ventilation have not changed much from the previous editions.
Taking advantage of this natural process referred to as passive ventilation is the most common way to vent an attic.
Continuous or individual soffits.
Hot air exhaust vents located at the peak of the roof allow hot air to escape.
Vent pipes shall terminate not less than 6 inches above the roof measured from the highest point where the vent intersects the roof.
Choose one of the following products to meet the recommended exhaust nfva of 528 square inches.
In our case the required 4 vents for the 1200 sq ft.
27 lineal feet required.
They are easy to install under the roof s overhang which is known as the soffit are generally hidden from sight and provide excellent protection from weather outdoor debris and pests while still allowing air to flow into the attic.
Effective attic ventilation systems reduce damaging heat and moisture in your attic promote energy efficiency by helping to reduce the load on your air conditioner in the summer and also reduce the risk of ice dam formation on your roof.
1 cubic foot is 12 x 12 144 cubic inches.
Typically building codes include minimum requirements applicable to attic ventilation.
If your roof is 1200 sq ft soffit floor space you will need 4 sq feet of roof ventilation.
Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge.
Ventilation can be accomplished using various products and techniques.
Next multiply the 4 square feet into cubic inches.
The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction.
In order to find the right calculator divide the attic floor space by 300 sq feet.
See the benefits of attic ventilation a new roof is more than just shingles.
Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca.
