Attic vents are a building code-required necessary component of residential roofs. They supply proper ventilation to the attic area. In the winter, attic vents supply proper air circulation to remove moisture buildup in the attic space thus protecting your attic insulation from moisture damage. Proper attic vent installation helps to reduce dry rot in the attic area and the roof structure. They also help to eliminate ice dams from building up on roof edges in cold weather climates. In the summer, attic vents allow excessive heat buildup to escape the attic area, thereby reducing cooling costs in the home.
It is best to install intake attic vents in the soffit area of your home and exhaust attic vents in the roof plane to provide for proper air circulation. Installing only gable vents, for example, will not allow for proper air circulation in the attic area.
There are a number of different attic vent designs that are broken down into two categories. Types of intake attic air vents include: Gable vents, soffit vents, circular vents, and static vents which are also known as roofline or eyebrow vents. Exhaust vents fall into two categories: Ridge vents and power ventilators.
Installing roof vents
- Determine the location and number of roof vents you want to install. Be certain to consult your local building code requirements.
- Basically, you want to allow at least 1 square foot of free vent area for each 150 square footage of roof or attic area.
- Space the roof vents evenly in the upper third of your roof.
- Remove the shingles in the roof vent location.
- Lay the vent base on the roof and mark around it.
- Using a circular saw or sabre saw, cut through the roof sheathing between the roof joists or roof truss members.
- Apply a good quality roof cement to the base of the attic vent.
- Place the attic vent in position and nail through the mounting flange into the roof sheathing with 1 1/2″ roofing nails.
- Coat the heads of the roofing nails with roof cement.
- Reinstall the shingles, being careful to overlap the attic vent mount base with the shingles row after row starting at the bottom of the attic vent and working toward the roof ridge.
- Seal the shingle edges with roof cement.
Installing soffit vents.
- Lay out the location of your soffit vents. Use a chalk line to mark the cuts.
- Set the depth of your circular saw blade to slightly more than the thickness of your soffit material.
- Seal the edges of the soffit vents by applying a coat of good quality roof cement or silicone caulk to the inner edge of the soffit vents.
- Install the soffit vents in the cutouts. Screw the mount flange into place using galvanized screws.
Verify that insulation in the attic is not blocking air flow from the soffit vents into the attic proper. If it is, you can install baffles in the attic over the exterior walls to keep the insulation in place away from the air passage way from the soffit vents. If fire blocking was installed over the exterior walls, drill holes in the fire blocking with a wood bit to allow air flow into the attic space.
Every roof penetration is a potential roof leak. Be careful to install the roof vents properly, paying attention to sealing all exposed joints and seams with a good quality caulk or roof cement.
Employ proper safety measures when working on any roof. Use safety gear including safety harness and safety line. Wear proper clothing for working on a roof, including sturdy work shoes. Secure your ladder to a stationary object or your home.
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