If you have a well-constructed roof, it will keep leaks, UV rays, and winds away from your home. However, after reinforcing the exterior part of your roof, you will need to reinforce the interior roofing components too. If the roof ventilation is poor, it will allow moisture and draft into your living room or bedroom, affecting your indoor air quality.
Your home might end up with condensation, growth of mold, and high humidity; all factors that affect the quality of your indoor air. Ensuring that the roof ventilation works is important in keeping your home comfortable at all times.
What is Roofing Ventilation?
Roofing ventilation refers to the free flow of air in your attic. Every day, moisture from cooking and showering finds its way into the attic. You have to remove this moisture from the attic through roof ventilation. Otherwise, the moisture has nowhere to go and might damage the interior components of your roof. If not removed, the moisture can reduce the efficiency of the insulation in your attic.
The effectiveness of your roof ventilation system is dependent on the balance between intake and exhaust ventilation. Experts can help you figure the correct balance. However, there are also local building codes relating to attic ventilation.
How does Proper Attic Ventilation Protect my Roof?
With proper ventilation, you will:
- Protect your roof from damage. The buildup of moisture and heat in your roof can cause stress to the shingles. This can result in premature damage of the roof. If the ventilation system is in good working condition, fresh air will push out the hot and humid air to protect your roof. When the temperatures are cold outside, icicles may form on your roof. These icicles form when snow falls on your roof then melt from the heat in your attic. The melted snow slides to the edges of your roof and forms icicles from there. If there is proper ventilation, the ice will sit on your roof since the attic will have lower temperatures. From there, the ice will naturally melt, and this reduces the formation of icicles. Although icicles look attractive at first, they add unnecessary weight on the edge of your roof, causing damage over time. Ventilating the attic keeps your roof safe from the weight.
- Lower the temperatures in the attic. When the hot air escapes from the attic, you save your air conditioning system from overworking to cool your home during hot summers. If your home is hotter upstairs than downstairs, then attic ventilation can be a solution. This will not only cool your home but also lower your utility bills as the air conditioner doesn’t work as hard to keep the home cool.
- Lower the chances of ice dam formation. When there is sufficient air flow in your attic, the roof stays cool, and this prevents the formation of ice dams that can damage your roof.
- Maintain the look of your roof. The humidity that comes from different areas in your home can condense on components of your roof. If left unattended, the condensation can cause growth of mold and mildew, resulting in unsightly stains on your roof. This may not cause any significant damage in the short run, but it affects your home’s curb appeal. In the long run, the condensation can cause rust and corrosion of materials, forcing you to replace some components of your roof.
Signs of Poor Roof Ventilation
Some of the signs that you need to check your ventilation system include:
Formation of Ice Dams
Is ice forming near the edge of your roof during winter? If yes, then you need to check your roof ventilation system. Snow dams are common in poorly ventilated roofs. These poorly ventilated roofs have hot decks, which heat up the snow at the roof’s ridge. The snow on the deck melts and flows to the cold edges of a roof. These cold edges freeze back the water into ice.
The water from the ice dams can seep into the shingles in your home or through any other cracks on the roof. When that happens, there will be water damages on the deck of your roof. The snow can also seep into the fascia and the eaves and cause further damage and weakens the roof structure.
If you store things in your attic, leakages can lead to the damage of these items. Leaks are challenging to clean up, especially during periods of extreme weather. As such, you need to ensure your home has sufficient roof ventilation.
Unbalanced Temperature in a Home
If your roof ventilation is not in good condition, some areas in your home might be colder or warmer than others. During the hot or cold months, you can feel the difference in the temperature of the different areas of a home. However, you can tell there is a problem if there is a steep increase in your electricity bill during the coldest or hottest months of the year.
The air conditioner or heater works more to cool or heat your home if the ventilation system in your attic is not in good condition. The lifespan of an overworked HVAC system reduces. Further, you may experience more frequent breakdowns and repairs. The sooner you solve the roof ventilation system, the easier it will be for both of you.
Signs of Decay
Signs of decay in components of your attic are an indication that condensation occurred in the attic. Signs of decay will include molds, weak adhesives, mildew, and rust on nails and other metallic parts. If there is no efficient airflow in the attic, the heat and humidity accumulate in the attic. The increased heat and moisture in the deck causes water damage on the roof components.
Moisture propagates the growth of mold and mildew, which further cause damage to the roof. The fungi can also pose a health hazard to people who suffer from allergic reactions to spores. Metal materials will corrode from the increased moisture in the attic. These materials include nails, fixtures, and electric boxes. You will see rust from these materials, and this is one of the most evident signs of insufficient airflow in the attic.
High humidity also lessens the grip on adhesives. The adhesives on the shingles will appear loose, and this exposes your roof to harsh weather conditions.
Mold leaves dirty-looking stains on several parts of the attic. When these dirty stains appear, it is an indication that the protective layer of the shingles is lost. If there is overgrowth of mold or mildew in your attic, it might be due to water seeping from the roof. This water can trickle to the ceiling and the walls and cause more stains. If the underlayment of the shingles is poor, the amount of water that seeps in will be more.
If the exterior paint in your home starts blistering or peeling, it may be due to poor ventilation. The peeling results from the moisture that is trapped in the attic due to rising humidity and excessive heat from the attic. Air needs to flow freely in and out of the attic. Areas near your kitchen and bathroom need more vents so that the humidity from these areas can escape with ease.
Types of Roofing Ventilation Systems
There are two main types of vents; the exhaust vents that let out air and the intake vents that bring in fresh air. The stale air is hot and humid, and it needs to escape the attic before it causes bad smells or damages the roof. Fresh air needs to come in to replace the air that escapes from the exhaust vents. If there is free flow of air into and out of the attic, your roof will be safe from water and heat damage.
Below are some of the most common roofing ventilation systems.
- Ridge Vents
Ridge vents are common exhaust vents. These vents sit at the peak of your roof and run from one end of the roof line to the next. Thanks to their position at the highest point of the roof, they are the most ideal for the release of hot air from the attic. Further, these ridges run across the entire roofline, allowing them to have a large surface area for the expulsion of air.
When combined with vents that sit at the bottom of the attic, such as soffit vents, they offer the best ventilation. Ridge vents offer vertical ventilation, which takes advantage of gravity and the lower density of hot air. Cold air comes up through the bottom vents and the less dense hot air rises to the top of the roof.
- Off-Ridge Vents
These vents are common on roofs with a three-tab off asphalt shingles. This vent sits close to the apex of the roof and thus the name. These vents are not popular, thanks to their small sizes that do not release enough air from the attic.
Their position just below the ridge or the apex of the roof restricts the amount of hot air they can expel from a home. The largest of these vents is four feet in length. These vents are ideal for homes that have peaks and valleys that hinder the installation of a ridge vent.
- Box Vents (Louver Vents)
Box vents are similar to off-ride vents but are more popular. You will see them in bunches on different parts of the roof to make them effective in releasing stale air from the attic. They have a square design are area available in a wide range of sizes to match the needs of a home. Installing one box vent or two will not offer enough ventilation for your roof.
- Powered Attic Vents
These are fans installed on your roof. These fans pull stake air from your home and expel it out of the attic. They will increase your electricity bills, but they are more effective during very hot or cold days. Note that, powerful fans can pull even the conditioned air out of a room and as such, they should never be placed near a window.
- Roof Turbines
Also known as whirlybird ventilation, these turbines have aluminum blades that rotate from the wind and as they do so, they pull air from the attic. They need wind traveling at about five or six miles per hour to initiate the rotation and start pulling stale air out of the attic.
- Cupola Vents
These vents are like chimneys, and they enhance the curb appeal of your home. They are towers with a roof on top and louvers on the sides. These vents are not common due to their expensive installation.
- Soffit Vents
These are intake vents for homes. They are the most popular and the most effective in letting in air into the attic. The vents install directly in to the eaves just underneath the roofline. There are different designs but all have small holes that allow in air into the attic.
These vents can be continuous or individual. Continuous vents are long and wrap around the eaves in a home. Their length makes them more effective than individual vents. Individual soffit vents are standalone vents that do not extend throughout the eaves.
- Gable Vents
These are triangular shapes vents on the side wall of a building. They are available in several sizes to meet the needs of different homes. These vents are not ideally combined with a vertical ventilation strategy as the cross breeze impedes the flow of air.
Benefits of Good Roof Ventilation
In case of poor ventilation, the moisture can cause deterioration of the roofing system, which further compromises the structural integrity of your roof. With proper ventilation, the moisture and the hot air in the attic leaves through ridge vents, exhaust vents, or powered vents.
Once the hot and humid air leaves, fresh air comes in through eaves and soffits. The soffits form the intake ventilation of the attics. For the hot and humid air to escape from the attic, cooler air needs to rush into the attic through the lowest point of the attic.
This free flow of air ensures that there is no condensation or heat that can cause damage to the roof.
You need to consult with your roofing contractor to know the best ventilation strategy for your home. The contractor will consider the size of your home, the design of the roof you have or want, your budget, and many other factors. With these factors in mind, they will design a ventilation system that will be the most effective for your home.