How Many Attic Rafter Vents Do I Need

To install the rafter vents staple them directly to the roof decking.
How many attic rafter vents do i need. They should be divided equally between inlet and outlet vents and they can be used in any combination that will work with your roof s design. As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. Based on your 1100 sq. The code associated issues.
To determine the total vent area measure the length and width of your attic in feet then multiply the two measurements to get the attic area then divide the number by 150 to get the vent space in square feet length x width 150. The general rule is that you must have one square foot of vent space for every 150 square feet of attic area. The rule of thumb on the amount of vent space needed is approximately 1 sq. Of vent for every 300 sq.
In order to facilitate this exchange of warm and cool air the general rule of thumb suggests installing at least 1 sq. Rafter vents come in 4 foot lengths and 14 1 2 and 22 1 2 inch widths for different rafter spacings. How many attic vent chutes rafter baffles do you need to optimize attic ventilation. Rafter vents ensure the soffit vents are clear and there is a channel for outside air to move into the attic at the soffits and out through the gable or ridge vent.
How many attic soffit vent truss chutes do i need. With the attic vent chute installed close to the bathroom vent discharge register the warm and humid air will always find its way back into the attic and often result in condensation mold growth. Per the 2009 irc r806 3 vent and insulation clearance insulation shall not block the free flow of air. Of vent space for every 150 sq.
You want to keep the warm moist air from the house from causing moisture on the underside of the roof. Multiply those two numbers and then divide by 150 to get the vent space square footage. From left to right air flows through the soffit vents up over the baffles allowing for the required roof venting. And this guideline you ll need a minimum of.
Near ridge of the roof. You may not need ventalation in each roof rafter bay but i doubt it will harm anything. So if your attic is 1 500 sq. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet.
Calculate how many rafter vents you need.