Residential Roof Ventilation Requirements

Ventilation standards are consensus documents published by professional or technical groups showing good practice.

Residential roof ventilation requirements.

Based on your 1100 sq. Government codes utility programs and private energy programs often cite national standards as part of their requirements. Pdf2015 international residential code for attic ventilation 145 kb. Blocking and bridging must be arranged so they do not interfere with air movement.

2018 international residential code. R806 1 ventilation required enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters shall have cross ventilation for each separate space by ventilating openings protected against the entrance of rain or snow. In no case should the amount of exhaust ventilation exceed the amount of intake ventilation. 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.

Air space no less than 1 inch must be provided between any insulation or obstruction and the roof sheathing. 2018 international residential code. That is openings doors windows and louvers to the outside should create a. Always have a balanced ventilation system.

Ansi ashrae standard 62 2 is the national consensus standard on residential ventilation in the united states. Near ridge of the roof. Contains sections covering roof framing roof sheathing and roof ventilation. 2015 international residential code for attic ventilation the code minimum ratio is 1 150.

As an example of what you can find in chapter 8 of the 2018 irc see. If your attic is enclosed california s building code states it should have cross ventilation. And this guideline you ll need a minimum of. On the upcodes website.

Before we explore how to ventilate an attic space it is prudent to understand how much ventilation is needed. The net free vent area nfva shall not be less than 1 150 of the area of the space being vented. Ventilation openings having a least dimension larger than 1 4 inch 6 4 mm shall be provided with corrosion resistant wire cloth screening hardware cloth perforated vinyl or similar material with openings having a least dimension of 1 16 inch 1 6 mm minimum and 1 4 inch 6 4 mm maximum. Chapter 8 roof ceiling construction.