Whole house fans powered attic fans.
Old attic pitched roof proper ventilation.
The building code lets you reduce that by half under some conditions but more roof ventilation is usually better.
The majority of the requirements related to attic ventilation have not changed much from the previous editions.
Your actual living space is sealed and insulated at the attic floor the attic is outside this envelope.
The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction.
Roof ventilation is crucial to attics as it positively affects the home inside and out.
If the slope of your roof is greater than 6 12 you will need more ventilation to reflect the extra volume of attic space.
Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.
Don t avoid ventilating your attic for fear you re letting cold air into the house.
Removal of excess heat and moisture will help the life of the roof and the efficiency of the hvac systems within.
Then aim for about 1 sq.
The success of a vented attic or roof deck relies on its airtightness.
In of vent opening per 150 sq.
Intake vents located at the lowest part of the roof under the eaves allow cool.
Pitched roof ventilation is beneficial in all climate zones and in.
Calculate 20 per cent more for 7 12 to 10 12 pitches and 30 per cent more for a pitch that is 11 12 or greater.
Baffles placed in this area channel intake air into either the attic space or vent chutes and also prevent insulation from falling into the soffit and blocking airflow.
Fans and vents may be installed on the roof system that will draw the air out of the attic space and exhaust it to the exterior.
The space above the top plate of exterior walls at the bottom of each rafter bay is especially important.
Pitched roof ventilation is achieved by creating air changes in the attic.
These fans may be controlled by a switch or a thermostat which detects heat build up in the attic space and automatically exhausts the attic space.
Most effective ventilation uses a ridge and soffit continuous ventilation system but even these designs can vary from roof to roof.
If you don t know how your roof vents work or if you re unsure about your attic ventilation in general you should talk to a roof inspector about your current system and any inherent weaknesses that may be at.
The following are the requirements taken directly from the irc.
