Design Attic Ventilation

Properly venting the attic ventilation is often a challenging task and it entails two processes.

Design attic ventilation. Also see insulation air heat leaks. These ventilation needs are calculated differently. There are some styles of vaulted ceiling homes or flat roof homes that have ventilation spaces within the roof itself and no attic. Air flows in through the soffit vents and out through the roof vents.

Intake vents located at the lowest part of the roof under the eaves allow cool air to enter the attic. Most building codes require a ratio of 1 150 ventilation space to attic floor space. After these are installed close off the gable end vents for best venting performance as discussed above. Hot air exhaust vents located at the peak of the roof allow hot air to escape.

The model building codes allow both vented and unvented roof assemblies. Enter square footage calculate or enter the square footage of the attic or area to be vented. Traditional design better attic venting is achieved with continuous soffit intake and ridge outlet venting. Attics or roofs can be designed and constructed to be either vented or unvented in any hygro thermal zone map 1.

If you see dampness or frost you need better roof ventilation and some attic vents. 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. Static roof line vents are effective for ventilation but generally aren t recommended due to issues with leaks. Soffit vents may leave air trapped at the top of your attic.

Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. For the best results place roof ventilation near the roof s peak and soffit vents in the eaves. The key to proper ventilation of your roof and attic is balance. Most effective ventilation uses a ridge and soffit continuous ventilation system but even these designs can vary from roof to roof.

Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Add continuous soffit vents at the eaves. You can also contact your local municipality to check on building code in your area. Use this tool to estimate the ventilation needs for your attic and get a list of broan attic ventilation product that will meet your needs.

Attic ventilation estimating tool. The first is the air entering through the circular soffit vents that incorporate a wire mesh referred to as bird blocks moreover there are other popular soffit vent styles including perforated lots or panels below the 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. Replacing your bathroom fan range hood or even installing a new fan.