Do You Need To Vent An Attic With Exterior Insulation

Direct all exhaust fans and vents to the exterior.

Do you need to vent an attic with exterior insulation.

Use eye brow vents that are on the top of the sloping roof surface near the soffit eave area. To completely cover your attic floor with insulation out to the eaves you need to install rafter vents also called insulation baffles. When the attic becomes part of the home to be heated and cooled open wall gable vents and roof vents are no longer feasible but the underside of the roof the sheathing and rafters can still get. The traditional remedy to this wetting is to slow the influx of moisture laden air into the cavity by using an interior vapor retarder and by ventilating the roof cavity to the exterior in order to facilitate the carry off of moisture i e.

First things first you need to go up into your attic inspect the condition of the insulation and calculate the current level of insulation. Complete coverage of the attic floor along with sealing air leaks will ensure you get the best performance from your insulation. On the other the florida solar energy center university of central florida found that attics with nominal natural ventilation and r 19 ceiling insulation do not need powered vent fans as it turns out because the insulation slows heat from moving down into the living space homes with well insulated attics don t see a significant. If the atmospheric combustion appliances start off in a vented attic the building code doesn t require those vents because the appliances are already connected to the outside and should get plenty of air.

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. 1 300 ventilation ratio recommended. Focus on the other ventilation you have in the attic. Though it s against building code to vent any kind of exhaust to an attic space many home builders have gotten away with this shortcut.

Insulation is used in an attic for cross ventilation to minimize potential for moisture accumulation and condensation to help energy savings and moisture control. Roof insulation thermal resistance at roof perimeter should be equal or greater to thermal resistance of exterior wall. Whether the home is old or new however anyone considering spray foam insulation would be wise to ask this question. Correct that mistake so that humid exhaust air doesn t get trapped in your insulation and ruin it.

Your attic should have a certain amount of insulation in it and the recommended level of insulation for your attic is dependent on where you live. Traditionally insulation materials that are placed inside of an attic will require air circulation within the attic space to assist in drying excess moisture in this indoor space. Inspecting your attic insulation.