Air handler ducts in attic vented or unvented compliance must be demonstrated via energy modeling with cbecc res software.
Attic ventilation requirements california.
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.
Mandatory minimum r 22 attic insulation unvented attics must be air sealed at roof deck eaves gables and penetrations.
So mechanical ventilation is now required in california to improve indoor air quality in all new residential construction when alterations are made to a residence and in residential additions of 1 000 sq ft or greater.
That is openings doors windows and louvers to the outside should create a natural flow of fresh.
The bottom of outdoor air intakes shall be located as high as practicable but not less than 10 feet 3048 mm above ground level.
If your attic is enclosed california s building code states it should have cross ventilation.
Ventilation openings shall have a least dimension of 1 16 inch 1 6 mm minimum and 1 4 inch 6 4 mm maximum.
Always have a balanced ventilation system.
Ventilators located in the upper portion of the.
1 8 mesh is also allowed.
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.
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Chapter 7a vent requirements.
Upper ventilators sha ll be.
No less than 40 and not more than 50 of.
Three frieze block vent holes can be seen in one section of blocking.
Gables to be insulated as exterior walls.
The chart below represents the net minimum area in square inches required for proper 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.
One or more of the following conditions are met.
Area shall be 1 300of the vented space provided.
Attic or rafter space.
In no case should the amount of exhaust ventilation exceed the amount of intake ventilation.
