Your home s r value score will guide you toward the type of insulation you need.
Does an attic need a co.
What your attic probably does not have is a set of code compliant stairs.
After confirming that your attic is air sealed you need to select insulation.
In general an attic s r value should be between r 30 and r 49.
Ideally there should also be plenty of soffit intake space their calculations recommend 336 net square inches of open soffit.
Let owens corning roofing help you calculate exactly how much ventilation you will need for a healthy and balanced attic with our 4 step ventilation calculator.
Calculate or enter the square footage of the attic or area to be vented.
However many building code officials have accepted unvented attics on a case by case basis when presented with compelling evidence such as hygrothermal modeling of proposed assemblies that the assembly will function properly.
That said air resistance and interference such as vent grates reduces the area of true ventilation.
Generally speaking you need a ratio of 1 300 where for every 300 square feet of ceiling space you need 1 square foot of attic ventilation.
According to the home ventilating institute hvi powered attic ventilators need to move a minimum of 700 cubic feet per minute cfm for 1 000 sq.
All you need to know about attic ventilation understand the pieces and parts that contribute to quality attic ventilation so that you can better cool down the space and prevent roof damage all.
Whole house fans need windows and doors open and attic fans need lots of soffit vents to suck cooler outdoor air up into the hot attic.
Ft of attic space for example 20 x 50 to be effective.
When i called the attic fan company i d intended to get 1 whole house fan installed however when the installer came out we realized that the upstairs of my home had a separate roof that wasn t connected to the lower level roof so he said i would need an attic ventilator on the lower roof.
To convert your attic to living space you cannot provide access via a ladder.
In other words the entire vent opening doesn t count as vented space.
Your attic may presently have a fixed ladder a pull down ladder or no ladder at all.
Without this open space the fans will not move much air.