Cbc Attic Ventilation Requirements

The bottom of outdoor air intakes shall be located as high as practicable but not less than 10 feet 3048 mm above ground level.

Cbc attic ventilation requirements.

Of attic space 1 150 ventilation ratio measured at the attic floor level ceiling. 1206 yards or courts. Attics must have a minimum of 1 square foot of ventilation openings for every 150 square feet of floor space. Chapter 4 special detailed requirements based on use and occupancy chapter 5 general building heights and areas chapter 6 types of construction.

1 square foot of ventilation for each 150. The net free ventilation shall be a minimum ratio of 1 150 of the area or space ventilated e g. 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. Attic ventilation cbc 1203 2 and crc r806 2 provide cross ventilation at all attic and enclosed rafter spaces.

The chart below represents the net minimum area in square inches required for proper ventilation. Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge. 1203 ventilation 1204 temperature control. If the attic is equipped with high and low ventilation openings the requirement is 1.

For large volume attics such as where roof slopes are greater than 8 12 designers also should consider increasing the amount of attic ventilation to account for the additional volume of attic space. 1208 interior space dimensions. Amendment also allows dsa. The uniform building code requires enclosed attic spaces enclosed rafter spaces and under floor areas to be ventilated by not less than 1 square foot for each 150 square feet of attic under floor area.

2016 cbc and the july 1 2018 supplement are being repealed and coadopted with oshpd. If installed above the roof they shall be located 18 inches 457 mm above roof level or 3 feet 914 mm above a flat roof where heavy snowfall is anticipated. 1209 access to unoccupied spaces.