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Roof Ventilation

Roof vents are a type of building material used to ventilate attics and ceiling areas. An effective roof ventilation system is essential in equalizing temperatures on both sides of a roof. It keeps your house cooler in the summer and prevents ice dams in the winter (if you live in a cold climate). Roof vents also play a role in improving the home's energy efficiency levels. If ventilation is poor & insufficient, condensation can develop causing insulation and wood deterioration, causing a horter lifespan than one that is properly ventilated. 

Determining how much ventilation is needed requires measuring your attic floor. Generally, one square foot intake and outtake ventilation is required for every 300 square feet of unheated attic floor space.When choosing vents for your roof, look for intake units that bring in fresh air, as well as exhaust vents that eliminate stale air. Considering factors such as roof design, vent operation and appearance is best when repairing or replacing roof vents for your home. 

Roof Doctor, Inc. will inspect your roof, check for vent damage or leaks, and check the felt paper of your roof around the vents for it's integrity.

Areas of Leaks:

  • Vents that are installed within the roof itself, such as static (eyebrow) units, pose a more serious risk for leaks than vents installed along the gables or soffits. These leaks can be stopped or prevented by sealing the crevice around the vent. Using caulk or foam to seal this space may work for a short period. However, a piece of metal that is custom-cut to fit tightly against the vent before caulking is the proper way to prevent roof leaks around your vents. This metal is called flashing. Flashing will help you to seal your vents and keep unwanted rain and air out of your home for many years.

Effectiveness of Vents:

  • Because hot air rises to the highest point of the roof, ridge vents tend to be the most effective. Gable vents, which are located in the walls at either end of a gabled roof, are fairly ineffective at removing warm air.

Amount of Vents Needed for a home:

  • Homeowners will need about one square foot of roof ventilation for every 150 square feet of attic space. You can use a few large vents or multiple smaller units to meet this guideline.


  • Compare appearance options. Low-profile static or eyebrow vents tend to be the least obtrusive and most visually appealing. Turbines and fans are highly visible and can negatively impact the roof's appearance. Tombstone-style vents are another attractive option, but these vents work best on steeply-sloped roofs.

Vent Screens:

  • Screens keep out insects and other pests, but may reduce ventilation effectiveness. If pest control is a priority, choose screened units, but add additional vents to ensure the attic is properly ventilated.


  • Always select vent materials that can hold up against severe weather. Galvanized and stainless steel units can withstand rain and high levels of moisture. Avoid non-galvanized steel, which may rust.

Types of Roof Vents:

Basic Roof Vents

  • When you need increased outtake ventilation, roof vents are a good choice to add near the ridge line. These covered fixed vents, which prevent rain from seeping in, are easy to install. They should be placed two feet apart for the best results. Because they have no mechanical parts, you don't have to worry about a malfunction.

Continuous Ridge Vents

  • This screened, water-shielded ventilation opening is available in 10-foot lengths and creates an even outtake airflow. It spans the entire gable roof ridge and is recommended for new construction. Unlike other vents requiring placement in several locations, a continuous ridge vent is one running piece. This makes it easier and quicker to install. It is available in colors to match the roofing, and is aesthetically pleasing because it is unnoticeable from street level.

Wind Turbine Vents

  • Installed near the roof peak, a wind turbine works by catching the wind or by air rising through the turbine. This causes the vanes to spin and provides effective ventilation near the top of the house by drawing heat and moisture out. The problem with these vents is that high winds can cause excessive spinning and wearing of the bearings. The vanes can also stick, and therefore stop rotating.

Soffit Vents

  • In order to achieve the most efficient roof ventilation, in addition to outtake vents it is equally important to have soffit vents, available in various sizes--3-inch round, 4X16 inch and 8X16 inch. Using a continuous length soffit vent is another option. Soffit vents are installed beneath the underside of a roof overhang. These vents permit air flow to the attic, or the space below the roof sheathing.

Gable and Dormer Vents

  • A gable vent in the triangular wall beneath the end of a gable roof is also required. This vent is a screened, louvered opening used to exhaust excess heat and humidity from an attic. It is available in wood or aluminum. If you have a dormer, a dormer vent is needed. Vents for both gables and dormers are available in many colors, styles and shapes to match the siding.
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