Adequate attic ventilation ensures warm, humid air exits your roof and cool air flows inside. By stopping excess heat and moisture from becoming trapped in your attic, it helps prevent a host of roofing problems, including mold, mildew, premature aging and ice dams.
What Are the Issues You May Encounter if Your Attic Isn’t Well-Ventilated?
Here’s an overview:
- Mold and mildew – Trapped warm, humid air in your attic creates a damp environment that’s the perfect breeding ground for mold, which eats away at wood and other components made from organic materials. If your allergies start acting up or notice black spots on your ceiling, have a roofing company inspect your roof as soon as possible. That’s because if mold-damaged roofing components aren’t removed immediately, they can affect other parts of your home.
- Premature aging – The trapped heat in your attic can accelerate the aging process of roofing shingles and drastically shorten their lifespan.
- Ice dams – In winter, inadequate attic ventilation can cause ice dams (which can cause water to back up and loosen shingles) to form near the edges of your roof. The trapped heat in your attic melts the snow that has accumulated on top of the roof. As the melted snow slides to the lower portions of your roof, it starts to freeze again, depositing ice on your roof’s edges.
How a Well-Ventilated Attic Can Prevent Roofing Issues
Warm air is lighter than cold air, so it rises to the top until it reaches your attic. To prevent warm air from becoming trapped in your attic, you need to make sure your roof has enough air vents. There are two types of air vents: exhaust vents (which allow warm, humid air to exit your attic) and intake vents (which allow cool air to enter). A properly designed roof ventilation system should have the right number of exhaust and intake vents.
How Much Ventilation Does Your Roof Need?
As a general rule, there should be a square foot of net free area (NFA) – the area through which air can pass – for every 300 square feet of floor area if your attic has a vapor barrier. However, if it doesn’t have a vapor barrier, there should be a square foot of NFA for every 150 square feet of attic floor space.
Why More Roof Ventilation Isn’t Necessarily Better
Keep in mind that more ventilation isn’t necessarily better. That’s because the airflow in your attic needs to be balanced. That’s why if you’re considering adding more air vents to your roof, you should consult a residential and commercial roofing services company.
How to Choose the Right Type of Air Vent
Another thing you should keep in mind is that not all vents can provide the same level of ventilation. To make sure your attic has enough ventilation, you need to choose one that’s suited to your local climate.
Here’s an overview of the most common types of exhaust and intake vents:
- Box vents – This type of air vent doesn’t have a lot of venting capacity, which means you need to install several of them to ensure your attic is well-ventilated. The problem with installing several box vents is that they tend to draw attention to themselves, which in turn may lower your home’s curb appeal.
- Ridge vents – Ridge vents are a smart choice if you want to keep your home’s curb appeal intact. Since they run along the roof peak, they’re easily hidden by shingles and won’t draw any attention to themselves.
- Turbine vents – On windy days, turbine vents (which take advantage of the wind to draw warm, humid air out of your attic) can provide better ventilation than most types of vents. However, the downside is that they won’t provide much ventilation during calm days.
- Cupola vent – Unlike other types of air vents (which are usually hidden from view), cupola vents are integrated into your home’s architecture. Keep in mind that cupola vents don’t have a lot of venting capacity, which means you’ll need to install another type of vent to supplement them.
- Gable vents – Like cupola vents, gable vents are integrated into your home’s exterior design. Gable vents are usually installed on the exterior walls of your attic or at the roof peak’s highest point in the gable.
- Under-eave vents – As the name suggests, under-eave vents are installed under the home’s eave.
- Rafter vents – Rafter vents or baffles prevent intake vents from being blocked by debris.
To learn more about your options, consult a roof repair and replacement contractor.
Purpose of Soffit Boards
Soffit boards are another component of your roof’s ventilation system. They are located under the fascia board (the long straight board your gutters are attached to) and have holes that allow fresh, cool air to enter your roof.
In addition to providing adequate ventilation, the soffit board also protects the rafters that form your roof’s structural support. That’s why it’s important to choose soffit boards made from materials that are durable enough to withstand your climate.
Here’s an overview of the most widely used soffit materials:
- Vinyl – Soffit boards made from vinyl are the most affordable option on the market. They’re also resistant to water and have lower maintenance needs than other types of soffit boards. However, they’re not the best choice if you live in temperate climates. That’s because vinyl is vulnerable to abrupt changes in temperature: it turns brittle when exposed to subzero temperatures and suffers warping when exposed to high temperatures.
- Aluminum – Aluminum soffit boards are durable, rust-resistant and easy to maintain, making them a smart choice if you live in rainy climates.
- Timber – Timber soffits are often installed in homes with traditional designs. They’re also a great choice if you want to add a sophisticated sense of elegance to your exterior. However, to preserve their curb appeal, timber soffits need to be routinely maintained.
- Fiber Cement – Fiber cement is made from cellulose fiber, sand, silica and Portland cement. It can resist moisture and insect damage is durable enough to withstand a wide range of climates.
To learn more about your options, consult one of your local roof repair and replacement contractors.
Why Insulation and Ventilation Always Go Hand in Hand
To maximize your energy savings, it’s important to make sure your roof and attic have enough insulation. Remember: insulation and ventilation always go hand in hand. Without adequate ventilation, water vapor in humid air will condense into droplets that can lower insulation’s R-value, which indicates its insulative capabilities. When insulation is exposed to moisture, it loses up to 40% of its R-value.
How much insulation does your attic need? ENERGY STAR® recommends installing insulation with a value of R-38.
What are the different types of insulation? Some of the commonly used ones are blanket batts and rolls (which is often installed in ceilings, unfinished floors, attic spaces and crawl spaces), foam boards (which have a higher R-value than other types of insulation) and spray foam (which can fit into small spaces easily). To learn more about your options and the local building codes’ insulation requirements, consult one of your local roofing contractors.
Orion Home Improvements LLC, a company with more than a decade of experience, offers a wide range of professional residential and commercial roofing services.