Attic Ventilation

JWK Inspections San Antonio Home Inspector
Proper Attic Venting needed on your San Antonio Home

Proper Attic Ventilation of your home consists of the soffit (intake) vents and the roof (exhaust) vents. Soffit vents (Inlet) are at the cornice / overhang area of your roof. JWK Inspections attic ventilation Illustration at left shows the soffit intake vent and the output roof vent which in this case shown is a ridge vent.  Roof vents (outlet) are near the top of the roof area and as shown in illustration besides ridge vents, there are gable end vents, turtle backs, turbine vents among others.
  Attic Roof Vents JWK Inspections
Proper ventilation, adequate air flow is needed in all attics (roof cavities). Without it, problems can occur with your home including but not limited to accelerated roofing material deterioration, decking material delamination and rot, mold & mildew due to moisture build up, energy loss and so on. Without proper air circulation in the attic moisture build up can occur and without the needed ventilation, it can't breafh to dry out.
Attic ventilation is an extremely important component of keeping a home or building in good condition. In the winter in poorly ventilated attics, warm moist air escaping from the below conditioned areas of the home condenses on the framing members and sheathing of the cooler attic space. In the summer, natural air flow in a well vented attic moves heated air out of the attic, protecting roof shingles and removing moisture. The ceiling insulation below the attic resists heat transfer down from the attic into the living area of the home.
Attic Ventilation with Baffles JWK Inspections

The total net free venting area needed for the attic must a minimum 1/300th of the attic area square footage. For example if you have 3000 sf of attic space you would need a minimum 10 sf of venting and that would need to be split up 50 - 50, half for soffit intake vents and half for the roof exhaust vents. Baffles, that are properly installed at the eaves prevent blown insulation from blocking the air flow from the intake soffit vents.
Attic Ventilation JWK Inspections - Baffles

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