Importance of Roof Ventilation
By: Dave Lamoureux
This is part 2 or 2
Now that the importance of ventilation has been established this article will talk about the common types of attic ventilation.
These are openings in the gable (peaks at the ends of the house) which are usually rectangular in shape but can also be triangle, oval or other such shape. This method provides for cross ventilation but only moves air in the upper portion of the attic. This is how many homes were built prior to the use of ridge vents. What many customers and contractor aren’t aware of is if a house has properly installed lower ventilation and upper ventilation then gable vents are actually counter- productive as they interfere with the convection action.
A ridge vent is a cut down the center of the roof at the peak, which exposes the rafters of the roof and allows for the escape of air. The opening is then sheltered with a baffeled cover which prevents water and critters from getting in. Finally it is capped with roofing shingles to blend in with the rest of the roof.
These are openings which are cut into the soffit (overhang) allowing for the intake of exterior air up into the attic space. It is very important to make sure that attic insulation is not blocking the outer wall and stuffed all the way down into the rafters, as the opening will be blocked and airflow will not be achieved. If the air space is blocked this can be remedied by installing what are called “baffles”. Baffles are simply Styrofoam pieces that are stuffed down in the rafters on the outer wall of the attic keeping the insulation pulled back allowing a channel for the airflow.
The best designed ventilation systems have what is called “convection” with lower intake of air and upper outflow of air. Cooler, dryer outside air will enter the soffit vent near the attic floor which in turn forces the existing heat and moisture filled air out through the ridge vent placed high on the roof peak.
Some houses are constructed in such ways that different types of ventilation, such as power venting and static vents, are required. United Home Experts is skilled in handling these unique challenges. Contact us today for a free no obligation roofing estimate.
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