Residential Roof Ventilation Requirements

2018 international residential code.

Residential roof ventilation requirements.

Based on your 1100 sq. Chapter 8 roof ceiling construction. 2015 international residential code for attic ventilation the code minimum ratio is 1 150. Near ridge of the roof.

Blocking and bridging must be arranged so they do not interfere with air movement. 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. In no case should the amount of exhaust ventilation exceed the amount of intake ventilation. 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. On the upcodes website. Government codes utility programs and private energy programs often cite national standards as part of their requirements. Most building codes require a ratio of 1 150 ventilation space to attic floor space.

Pdf2015 international residential code for attic ventilation 145 kb. 2018 international residential code. Before we explore how to ventilate an attic space it is prudent to understand how much ventilation is needed. Ventilation can be accomplished using various products and techniques.

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. Always have a balanced ventilation system. Contains sections covering roof framing roof sheathing and roof ventilation. Ansi ashrae standard 62 2 is the national consensus standard on residential ventilation in the united states.

Ventilation standards are consensus documents published by professional or technical groups showing good practice. If your attic is enclosed california s building code states it should have cross ventilation. Air space no less than 1 inch must be provided between any insulation or obstruction and the roof sheathing. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca.