Does An Attic Need A Co

Ft of attic space for example 20 x 50 to be effective.

Does an attic need a co.

Calculate or enter the square footage of the attic or area to be vented. 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. What your attic probably does not have is a set of code compliant stairs. In other words the entire vent opening doesn t count as vented space.

To convert your attic to living space you cannot provide access via a ladder. 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. 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. There are many types to choose from including blown in cellulose batt such as fiberglass mineral wool or cotton.

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. Your attic may presently have a fixed ladder a pull down ladder or no ladder at all. 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. In particularly cold climates you might go up to r 60.

That said air resistance and interference such as vent grates reduces the area of true ventilation. Ibc requires ventilation in attics and crawl spaces and does not address the unvented attic concept. 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. Ideally there should also be plenty of soffit intake space their calculations recommend 336 net square inches of open soffit.

After confirming that your attic is air sealed you need to select insulation. 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.