Old Attic Pitched Roof Proper Ventilation

Removal of excess heat and moisture will help the life of the roof and the efficiency of the hvac systems within.

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. 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. If there are asphalt shingles on your roof the attic must be ventilated to comply with the terms of the manufacturer s warranty. 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.

The following are the requirements taken directly from the irc. Most effective ventilation uses a ridge and soffit continuous ventilation system but even these designs can vary from roof to roof. 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.

The success of a vented attic or roof deck relies on its airtightness. The open area of a vent is sometimes listed on the roof air vent as nfva net free vent area. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.

Your actual living space is sealed and insulated at the attic floor the attic is outside this envelope. 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. 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. Intake vents located at the lowest part of the roof under the eaves allow cool.

Whole house fans powered attic fans. If not measure the size yourself. Pitched roof ventilation is beneficial in all climate zones and in. If the slope of your roof is greater than 6 12 you will need more ventilation to reflect the extra volume of attic space.

The majority of the requirements related to attic ventilation have not changed much from the previous editions. In of vent opening per 150 sq. 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.