Old Attic Pitched Roof Proper Ventilation

Intake vents located at the lowest part of the roof under the eaves allow cool.

Old attic pitched roof proper ventilation.

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. Then aim for about 1 sq. If there are asphalt shingles on your roof the attic must be ventilated to comply with the terms of the manufacturer s warranty. Most effective ventilation uses a ridge and soffit continuous ventilation system but even these designs can vary from roof to roof.

The majority of the requirements related to attic ventilation have not changed much from the previous editions. If not measure the size yourself. The following are the requirements taken directly from the irc. The success of a vented attic or roof deck relies on its airtightness.

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. Pitched roof ventilation is beneficial in all climate zones and in. In of vent opening per 150 sq. The space above the top plate of exterior walls at the bottom of each rafter bay is especially important.

Removal of excess heat and moisture will help the life of the roof and the efficiency of the hvac systems within. Don t avoid ventilating your attic for fear you re letting cold air into the house. 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. 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. The open area of a vent is sometimes listed on the roof air vent as nfva net free vent area. The building code lets you reduce that by half under some conditions but more roof ventilation is usually better. Pitched roof ventilation is achieved by creating air changes in the attic.

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. 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. If the slope of your roof is greater than 6 12 you will need more ventilation to reflect the extra volume of attic space.