attic insulation and ventilation

What is attic ventilation? Balanced intake and exhaust

“Ventilate” comes from the Latin word for “to fan.” Simply put, it’s the action of moving air. Out with the hot. In with the cool. And that’s exactly how ventilation works. It provides conditions that allow air to flow. Every time stale, the overheated air in your home or attic is vented out and fresh air is pulled in to replace it, you have what is known as an “air exchange.”

But ventilation is much more than a simple breeze blowing through your house. It’s a
the process that provides a steady, high volume of air movement. Think about it as a system of components, all sized and positioned to provide constant intake and exhaust of air. Roofing Above All calculates the balanced ventilation your home requires, enabling you to effectively “wash” the entire attic by pulling air from the intake vents low on the roof’s edge or in the soffit to the vents at the ridge in the high areas.

More is better, right?

A sure sign of poor ventilation is an unbearably hot attic in the summer. Another thing to check is evidence of moisture, such as mold, mildew, rusted nail heads, damp or compressed insulation or wood rot. In an effort to alleviate moisture buildup, some homeowners misplace ventilation products and actually short-circuit the home ventilation system. When designing your custom balanced ventilation system, Roofing Above All never recommends a combination of different types of exhaust vents, like power vents with ridge vents or gable vents with can vents. When these combinations are used, competing vents pull air from each other instead of from pulling from the intake vents, leaving the lower attic area unventilated and vulnerable to moisture build-up and the damages that result.

roof ventilation diagram

Bath and kitchen ventilation, just as important as the rest!

Now that you’ve mastered proper attic ventilation, don’t spoil it with improperly installed bath and kitchen vents. If bath and kitchen vents are left pouring into the attic, instead of vented outside the roof via a dampered vent, your attic moisture will continue to present a problem. Let the ventilation pros at Ridgecon ensure your bath and kitchen vents aren’t throwing off your balance ventilation equation.

Just exactly what causes ice dams?

Ice dams are barriers to water runoff on the roof. They usually form at the roof edge, just above the gutter, in cold, snowy climates. They form when snow melting on warmer areas of the roof, usually near the ridge, runs down and refreezes at colder roof overhangs. Warm spots on the roof are caused by the heat that escapes from the living space into the attic. Once this cycle of melting and refreezing begins, a barrier is formed, trapping the snowmelt and allowing it to flow up and under shingles.

ice dam illustration

As the water begins to penetrate sheathing, insulation, wall cavities, and sheetrock or plaster:

  1. Paint can begin peeling on both inside and outside walls
  2. Roof coverings, fascia, and gutters can be damaged
  3. Structural damage can result from the weight of the ice dam

Homeowners usually blame their gutters, since that’s where the problem appears to be. But newer, wider, deeper gutters won’t solve the problem. Nor will additional layers of insulation alone. What will solve it is adequate ventilation combined with proper levels of insulation.

Ventilation and ice dams. What’s the connection?

balanced_ventBalanced Vent The key to solving ice dams is to create a cold roof. A cold roof occurs when the temperature inside the roof sheathing near that of the outside air temperature. To achieve this condition, large volumes of outside air must enter low on the roof through the intake vents, sweep along ridge rafters, then exit at vents near the ridge. To prevent trapping warm air in the attic, an equal balance must be established between intake and exhaust air volumes.

Since such a ventilation system is bringing cold air into an attic, it’s important that your insulation has at least an R-value of 49, to minimize heat loss at the attic floor. As an added precaution, Roofing Above All always uses waterproofing shingle underlayment. It provides a waterproof barrier beneath roof shingles that pooled water from melting ice dams and driven rain cannot penetrate.

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