Does My Attic Need To Be Vented

The model building codes allow both vented and unvented roof assemblies.

Does my attic need to be vented.

What your attic probably does not have is a set of code compliant stairs. To get down to brass tacks the question becomes less about should you and more about how much you need. In other words the entire vent opening doesn t count as vented space. My question is this.

When we seal the attic with spray foam it s as tight as a butter tub. But when it comes down to it it can get a little complicated. During winter the primary cause of attic moisture issues stem from warm moist air infiltrating into the attic space from the inhabited areas and condensing on cold surfaces. Attics or roofs can be designed and constructed to be either vented or unvented in any hygro thermal zone map 1.

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. The choice of venting or not venting is a design and construction choice not a requirement determined by the physics or by the building code. When done correctly attic venting can reduce the potential for condensation in winter and summer. Each home is unique carrying challenges and structural requirements to match.

To convert your attic to living space you cannot provide access via a ladder. Yes using spray foam we have added your attic to the conditioned space. The easy answer is yes your attic should absolutely be vented. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.

Here s the answer to the question posed in my article title. In a properly designed passive system air enters through the soffit. That said air resistance and interference such as vent grates reduces the area of true ventilation. 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. Our thermostat is nearby this half closet. Intake vents located at the lowest part of the roof under the eaves allow cool. Your attic may presently have a fixed ladder a pull down ladder or no ladder at all.