Roof vents are an important part of your home. They extend the life of your roof by preventing condensation in the attic that can damage the roof above. They also help regulate temperature and expel excess heat in warmer months. In addition, roof venting is required by most building codes. So it is important to do your homework and find out what you need to know about installing roof vents. That will help you to maintain your roof and comply with local building codes.
Why Roof Ventilation Matters
Your roof is the most important part of your home. It protects you from the elements and provides the most basic shelter. A roof is also one of the most expensive parts of your home to replace. Roof ventilation is key to maintaining your roof in its best condition. Avoiding roof damage can mean avoiding costly repairs to other parts of your home. A damaged roof can have a cascading effect.
The Effects of Roof Damage on The Rest of Your Home
Damage to your roof can cause leaks that damage other parts of your home. Ceilings, walls, and floors are all susceptible to damage from a leaking roof. Damage to a carpeted area can require expensive repairs, even replacing the entire carpet. Moist ceilings, walls, and floors can also breed molds and fungi that require extensive professional cleanup. A leak that is not attended to quickly can become a major disaster. It may require opening up ceilings for days or weeks while a heavy duty dehumidifier sucks the moisture out of the air and affected materials.
Roof damage can also result in small spaces in your roof that become entry points for pests. Pests such as insects and rodents can cause major damage to your home that requires professional intervention and expensive cleanup. Rodents can infest the spaces in the walls of your home. Their nests are filled with excrement that carries numerous diseases that can affect humans. Because nesting and fecal materials are easily airborne, rodent extermination and cleanup can be an expensive job best left to professionals.
Roof damage that is left unchecked can eventually require a full roof replacement. Roof replacement is one of the most expensive repairs you will have for your home. A new roof can cost thousands of dollars, and insurance may not always cover the full cost. Avoiding roof damage and keeping your roof in good condition is the best way to save money, avoid damage, and protect your investment in your home.
How Much Ventilation Do You Need
Ventilation is vitally important to the maintenance and longevity of your roof. Without proper ventilation a roof can sustain damage from moisture and condensation that accumulate in the colder months of the year. Knowing how much ventilation your roof requires is an important consideration. Inadequate roof ventilation can result in roof damage. Generally there are not many negative effects from too much ventilation. However, too much airflow through your attic can affect the temperature of your home and have other undesirable effects. So it is best to know how much ventilation you need exactly, and then to err on the side of more than less.
Calculating how much roof ventilation you need is relatively simple. The main contributing factors are the slope of your roof and the size of your attic space. The main goal in installing roof ventilation is achieving the right balance between intake and exhaust. Generally, you want to make sure that the two are about equal, but it is best to err on the side of too much intake over too much exhaust.
Calculating Net Free Area
The number that you are looking for when figuring ventilation is “net free area” (NFA). NFA is the amount of open space for air to flow in and out of your attic area. Different types of vents have different amounts of NFA per square foot or per vent.
To calculate the amount of intake and exhaust NFA you need, first determine the square footage of the floor of your attic. If your attic floor has a moisture barrier, figure one square foot of NFA per 300 square feet of floor space. The total resulting NFA should be split evenly between intake and exhaust. So an attic that is 1200 square feet will require 4 square feet of NFA, 2 for intake and 2 for exhaust.
If your attic floor does not have a moisture barrier, calculate one square foot of NFA for every 150 square feet of attic floor space. The division between intake and exhaust remains the same.
If your roof slope is steeper than a typical roof, that is greater than 6:12, you will need more NFA. That is because the steeper slope means more total airspace in your attic. If your roof pitch is 7:12 to 10:12 add 20% to the standard calculation of NFA. For roofs with a pitch of 11:12 or more, add 30%.
Types of Intake
The most common type of intake is a soffit intake. The soffit is the area underneath the part of your roof that overhangs the exterior of your home. Either single or continuous soffit venting is available. Your roofer can help to determine the best type of soffit venting for your roof. In general, make sure that you have adequate NFA, especially on the intake side. A common mistake is to provide too little intake NFA, so that airflow is restricted.
Soffit venting is a great way to go because of its many benefits. It is usually tucked away where you don’t see it, preserving the look of your home. Also, its location under the eaves of your home provides added protection. It can keep debris from clogging or blocking you intake vents.
Another type of intake is actually both an intake and exhaust vent. Gable end venting is a slotted metal or wooden piece of siding similar to a heating vent in your home. It is installed on the exterior wall of your house near the gable, where it has access to the attic. Gable end vents rely on wind to push the air into the vent, so they are best to use on a side of your home that faces the oncoming wind. It is recommended that there is an average breeze of 5 mph or more to make this kind of vent work properly.
There are a number of different types of exhaust venting. Most exhaust venting relies on the fact that warm, moist air naturally flows upwards. Exhaust vents are placed higher than the intake vents. This causes air to flow up and out of the exhaust vents, which then draws air through the intake vents into the space left behind.
One common type of venting is ridge venting. Ridge venting is installed along the ride of your home’s roof, taking full advantage of moist, warm air’s upward flow. It is basically a long metal sheet that is bent to fit the ridge of your roof. It is installed slightly raised from the roof, creating an open slot along the underside of its length. The ridge vent will look different from the rest of your roof, so your roofer may install shingles over the ridge vent to hide it from view.
Static vents come in a number of shapes and sizes, but all follow the same principle of air flow. These vents usually protrude from the roof and have small openings that allow air to move up and out.
Gable end vents, as noted above, work well in areas with a steady breeze. Another type of exhaust vent that makes use of the breeze is a turbine vent. This vent has non-motorized turbines that are turned by the breeze. The spinning turbines draw air up and out of the attic.
A less common type of exhaust vent is the powered or motorized vent. This vent works like a turbine vent, but the turbines are turned by a motor. The motor can be set to work according to a thermostat or moisture monitor.
Always Use a Reliable Roofer
When installing ventilation for you roof, you need to know what you are doing. That is because adequate ventilation must conform to both the needs of your home and local building codes. Poorly installed ventilation can result in serious damage to your roof and your home. The experts at Eagle Watch Roofing are experienced in the installation of roof venting. They can inspect your roof, including your ventilation, and make any repairs that are necessary. This will keep your roof in its best condition for its full life expectancy or even beyond. Contact them today for a free estimate.