Residential Roof Ventilation Requirements

2018 international residential code.

Residential roof ventilation requirements.

On the upcodes website. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. 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. The net free vent area nfva shall not be less than 1 150 of the area of the space being vented.

Ventilation standards are consensus documents published by professional or technical groups showing good practice. As an example of what you can find in chapter 8 of the 2018 irc see. Blocking and bridging must be arranged so they do not interfere with air movement. Government codes utility programs and private energy programs often cite national standards as part of their requirements.

Chapter 8 roof ceiling construction. Air space no less than 1 inch must be provided between any insulation or obstruction and the roof sheathing. Near ridge of the roof. Pdf2015 international residential code for attic ventilation 145 kb.

Contains sections covering roof framing roof sheathing and roof ventilation. Always have a balanced ventilation system. Most building codes require a ratio of 1 150 ventilation space to attic floor space. 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.

And this guideline you ll need a minimum of. Based on your 1100 sq. In no case should the amount of exhaust ventilation exceed the amount of intake ventilation. If your attic is enclosed california s building code states it should have cross ventilation.

That is openings doors windows and louvers to the outside should create a. 2015 international residential code for attic ventilation the code minimum ratio is 1 150. Ventilation can be accomplished using various products and techniques. Ansi ashrae standard 62 2 is the national consensus standard on residential ventilation in the united states.