Roof Ventilation For Finished Attic

Before we explore how to ventilate an attic space it is prudent to understand how much ventilation is needed.

Roof ventilation for finished attic.

Intake vents located at the lowest part of the roof under the eaves allow cool air to enter the attic. There was ridge vent originally installed but sealed up with spray foam closed cell. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. The insulation is spray foam open cell directly on the underside of the roof deck min r19 and on the inside of the exterior walls.

If you re finishing your attic insulating it to the proper r value can cause a dramatic loss of. The recommended ventilation ratio to provide for vented attic assemblies when an air barrier is present is the 1 300 ratio as specified by most building codes. Ventilation can be accomplished using various products and techniques. How attic ventilation works effective ventilation in an unfinished attic usually includes intake vents down low along the soffits and exhaust vents up high at the peak or roof ridge.

Without properly ventilating the roof your finished space can be just as unpleasant as an unfinished attic. Roof insulation thermal resistance at roof perimeter should be equal or greater to thermal resistance of exterior wall. In other words the entire vent opening doesn t count as vented space. Permanent stairs carpet heat ceilings drywall completely finished.

Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. Since parts of a finished attic are usually very close to the roof insulation often blocks proper ventilation that is needed under a roof structure. Most building codes require a ratio of 1 150 ventilation space to attic floor space. Lowering the temperature in the attic can help reduce air conditioning energy costs and roof deck temperature optimize the service life of a roof covering and minimize ice damming.

To lower attic temperatures and to remove excess moisture. 5 year old house finished attic. Hot air exhaust vents located at the peak of the roof allow hot air to escape. 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.

Why attic ventilation attic ventilation serves two main functions. This allows for a continuous flow of air through the space. Without properly insulating your finished attic room will also be cold in the winter. Vent the roof deck.

To effectively ventilate your roof create a 1 in. Insulate your finished attic properly choose your insulation. 1 300 ventilation ratio recommended.