Common Roof Ventilation Problems and How to Fix Them

roof ventilation system on a roof

If your home is blisteringly hot in the summer, heat waves are not the only thing to blame. Poor roof ventilation also can increase the heat in your home, which in turn increases energy costs. To protect your home from heat or water damage, your attic space needs good airflow.

There are many common roof ventilation problems, and homeowners need to know what to look for so they can spot these issues as well as how to fix them.

What is Roof Ventilation?

A roof ventilation system consists of small openings on or near the roof that allow air to circulate in and out of the attic.

Think of a ventilation system as being a house’s breathing system: exhaust vents allow the house to exhale while intake vents allow it to inhale. Its purpose is to protect your attic from overheating and accumulating excess moisture.

Too much moisture buildup can cause extensive damage to the underside of the roof and the attic area. Home activities like the following can produce condensation:

  • Showering
  • Doing laundry
  • Washing dishes
  • Cooking

Then, the moisture travels upward into the attic space. So, without roof vents, too much warm air gets trapped inside the attic – making it unreasonably hot.

Types of Roof Ventilation

vent on top of a roof
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A good roof ventilation system is not just about having the right number of roof vents for your home. You also must have the right type of vent since every home needs the correct combination of exhaust and intake vents.

If your roof only has exhaust vents, it will be unbalanced. A mixture of exhaust and intake vents is essential for every roof.

Exhaust Vents

Pushing hot, stale air out of the attic, these vents are placed at the top of the roof or on the roof ridge. Some examples are:

  • Box vents
  • Cupola vents
  • Dormer vents
  • Gable vents
  • Power vents
  • Ridge vents
  • Solar vents
  • Turbine vents, also known as whirlybirds

Intake Vents

To help pull cool air into the attic, intake vents are usually placed near the floor of the room. A few examples of this type of vent include:

  • Gable vents
  • Soffit vents

Additionally, roof vents are split into two categories based on their power source:

  • Power vents: Also known as mechanical vents, they require electricity or solar power to work.
  • Passive vents: These vents rely on wind to move, making them completely reliant on external forces to work. They are also called natural vents.

Finding the right roof vents for your home can be difficult, and it depends on the roof design, slope, and size. Homeowners also will need to consider if they want an active or a passive vent. Passive vents require less electricity, but they are not as effective as power vents.

Problems Caused by Poor Ventilation

ridge vents on shingle roof
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A properly working roofing ventilation system saves homeowners money on cooling and heating costs. On the other hand, poor ventilation causes issues for your home, such as moisture damage or temperature discrepancies that form hot or cold pockets of air in your living area.

Moisture Buildup

Condensation from daily household activities accumulates and wafts up to your roof, where it gets trapped without good air vents to exhale the moisture out of your home. If left unchecked, it can damage the roof decking, underlayment, shingles, or attic insulation.

Sagging, spongy roofs, or roof leaks are a sign of poor attic ventilation and too much moisture buildup. If the water damage is too extreme, you may end up having to replace the entire roof.

Aside from damaging the wooden structure of your home, moisture damages metal surfaces, as rust will develop on exposed nails, venting duct straps, or flashing.

Note: During winter, your attic is most likely to develop moisture buildup. When the air outside is cold, the water won’t evaporate as quickly, and moisture can get trapped in the attic if it is poorly ventilated.

High Energy Bills

If the energy costs of your home have recently skyrocketed, a poor ventilation system may be to blame.

When your attic space overheats, it increases temperatures in the rest of the house. This puts more strain on your HVAC unit, causing it to work overtime to compensate for the extra heat in the house. It would take more power for the HVAC unit to keep your house cool, ultimately resulting in more energy expenses.

Peeling Paint

Paint peeling or blistering, whether on the exterior or interior of a home, is likely a sign of moisture buildup. So, if you notice the paint is peeling a lot on your home, it may be caused by a ventilation problem.

Mold Growth

The growth of mold, mildew, fungus, algae, rust, or rot in your attic is a sign of underperforming roofing ventilation, as it means there is too much moisture buildup in your attic. A musty odor in your attic may be a sign of mold growth.

Attic mold growth can be harmful and cause allergic reactions, respiratory problems, or trigger asthma attacks.

If a lot of rust has affected your roof vents, they will have to be replaced. Rust corrodes the roof vents and may eventually hinder the mobility of its mobile components. In severe cases of rust, the turbines might get stuck and will be unable to function.

Overheated Attic

Naturally, attics are prone to overheating during the summer. An unventilated attic can reach temperatures up to 150 degrees Fahrenheit, and all that hot air gets trapped inside your attic with no way out.

Signs of an overheated attic are:

  • HVAC unit working overtime
  • Energy bills increase
  • Indoor temperatures vary widely from one room to another
  • Cracked shingles
  • Granule loss
  • The ceiling or roof is hot to the touch during the day

If you don’t want your attic space to turn into a sweltering sauna that heats up the rest of your house, ensure your roof ventilation system is working properly. Otherwise, an overheated attic will ultimately shorten the lifespan of your roof.

Ice Dams

Good ventilation decreases the likelihood of an ice dam forming on your roof since it cools down the temperatures in your attic. This may sound like a bad thing since homeowners might assume that a hotter attic during the winter is better for keeping the house warm.

But ice dams are caused when the attic and surface of the roof are warmer than the outside air. When it snows, the warmth and heat radiating from the roof melt the snow, but the water slides down your roof only to refreeze at the roof’s edge. As a result, this causes a buildup of ice on your roof that prevents any melting snow water from escaping, creating an ice dam.

Damaged Roofing Materials

roof damage caused by hail
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Poor ventilation can cause overheating and damage rafters, wood framing, shingles, insulation, and underlayment. When there isn’t enough circulation inside the attic space, it can turn into an oven, baking your roof’s asphalt shingles from below. Poor attic ventilation can cause significant damage to your roofing materials:

  • Sagging or spongy roofs
  • Blistered shingles
  • Warped or rippled shingles
  • Cracked shingles
  • Damp or soggy roof decking
  • Shingles age prematurely
  • Shortens a roof’s lifespan

When exposed to too much moisture buildup, roof decking becomes soggy or damp, which dissolves the adhesives holding the roofing shingles together and holding them down to the roof decking. When the adhesives dissolve, it results in a sagging roof.

Overworked HVAC Unit

If your air conditioning is working overtime, it’s probably a sign of improper roof ventilation. A hot attic results in a hotter home, which in turn requires the air conditioning unit to be used more frequently. And the more your HVAC unit is overworked, the more energy costs go up.

The extra strain on your air conditioning unit has long-term negative effects. The wear and tear will decrease the lifespan of your HVAC unit or lead to the unit requiring repairs much sooner.

How to Fix Poor Roof Ventilation

Try a Roofing Inspection

Before you commit to replacing, installing, or repairing any roof vents, you might want to confirm what the problem is first. Hiring a professional roof contractor to take a look at your roofing system is a good way to figure out if it needs any repairs. Your roofer can let you know if there’s anything wrong with your roof and what can be done to fix it.

It is recommended to have your roof inspected once a year. During the annual inspection, your roofer also can inspect your roof vents and identify any possible problems with the ventilation system.

If you want to do the inspection yourself, look out for:

  • Roof vents that have been knocked askew by rough winds
  • Leaks
  • Mold or fungal growth in the attic
  • Loose or damaged insulation
  • Insulation blocking vent entryways
  • Loose ductwork
  • Signs of wildlife, like animal droppings or nesting materials
  • Warped shingles
  • Sagging roof
  • Spongy roof
  • Signs of moisture damage
  • Damaged wood
  • Curled, cracked, or buckling shingles
  • Debris stuck in vents
  • Condensation in the attic

Note: It’s good practice to check your roof vents for damage after any rough storm or high-speed winds pass through your area.

Install a New Vent

attic vent installation
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For roof vents that are broken or damaged beyond repair, you may need to replace them.

To install a new roof vent:

  1. Remove the old roof vent.
  2. Use a crowbar to loosen up the surrounding shingles.
  3. If insulation is poking out and blocking the vent opening, push it back into place to ensure it no longer blocks the vent airway.
  4. Measure the hole that the new roof vent needs to cover.
  5. Place the new roof vent over the hole.
  6. Screw the roof vent down. If there aren’t any visible nail holes, the general rule is that a roof vent needs 4 to 6 nails to stay properly secured to the roof.
  7. Caulk the nails to seal the vent and prevent it from leaking.
  8. Replace any insulation that had to be removed during the roof vent installation.
  9. After the installation, you should check to ensure your roof vent is working properly.

Asphalt shingle roofs or wood roofs are the easiest types of roof for a DIY roof vent replacement. It’s more challenging to install a new roof vent on various types of slate or metal roofs. But since working on top of a roof is dangerous, it’s better and safer to call a pro roofer for the job instead.

Secure the Vents

Fierce storms with rough winds may spell bad news for your roof vents. Gusty winds can knock roof vents askew, which not only stops the roof vent from working but also causes rainwater to get into your attic.

Other times a loose roof vent might be caused by loose or damaged screws. Fixing this problem usually involves tightening the screws and re-securing the roof vents.

Place Vents Properly

There’s an art to roof vent placement, so you can’t place them at random anywhere on the roof and expect them to work properly.

Roof vents should be placed evenly along the roof, not crowded altogether. Otherwise, the ventilation system will not be able to operate efficiently. Also, if vents are installed too close to the eaves, this can hinder the airflow inside the attic.

Add More Roof Vents

If your roof doesn’t have enough ventilation, the simple solution is to install more roof vents on your roof in order to create a balanced flow of air through your attic. Remember that every roof needs an equal number of intake and exhaust vents for an effective ventilation system.

To calculate how many roof vents your home needs, the rule is that for every 300 square feet of attic floor space, you need 1 square foot of roof vents, which equals one roof vent.

For roofs that don’t have a vapor barrier, try following the 1:150 ratio. This means that for every 150 square feet of flooring, you will need 1 square foot of roofing ventilation.

Unclog the Vents

Since roof vents are placed outside, they are constantly exposed to the elements. Debris, like leaves or twigs, can get stuck in the roof vents.

Usually, fixing a clogged roof vent should be a simple matter of removing any debris caught in the roof vent by hand. Wear gloves to protect yourself from sharp sticks. There are several types of debris that can get clogged in the roof vents, such as:

  • Cobwebs
  • Insulation
  • Leaves
  • Snow
  • Twigs

If needed, use a brush to sweep debris away from the roof vent. You also can vacuum out the roof vent to remove any dust or leftover debris. A leaf blower or air nozzle can be used to blast debris out of your roof vent.

For soffit vents, you should clean them every two years to keep them clean of dust and debris.

Benefits of Proper Roof Ventilation

Roof vents are an essential part of a roofing system and come with a lot of benefits that save homeowners money on energy costs. Additionally, proper roof ventilation protects homes from damage, which saves you the stress of having to pay for costly repairs.

  • Extends roof’s lifespan. Without proper ventilation, your attic and roof suffer from heat and water damage. Your shingles may age prematurely and have to be repaired or replaced before your roof reaches the end of its lifespan.
  • Prevents mold growth. Mold, mildew, rot, and fungus growth occur if there is too much moisture buildup in your attic.
  • Lower energy bills. Vents cool down your attic space, which in turn keeps the house cooler. The less electricity that your HVAC unit uses to keep your house cool, the less you have to spend on energy bills.
  • Defends against ice dams. While good ventilation may not prevent all ice dams from forming on your roof, it evens out temperatures between your attic and the outside air, helping prevent ice dams from forming on your roof.
  • Improves indoor temperatures. A lack of good roof ventilation can cause pockets of hot or cold air to form in your home, so you may notice a drastic temperature change from room to room if you have a poorly working vent system.
  • Extends the lifespan of the HVAC unit. A roofing ventilation system prevents your HVAC unit from being overworked. The less it is used, the longer it lasts. It also can save time on air conditioning repairs and reduce the chances of your HVAC unit breaking down.

Cost to Install a Roof Vent

An important consideration of any investment in home improvement is, of course, the price tag. If you’re looking to install a new roof vent, you’ll want to find an option within your budget since certain types of roof vents are more expensive than others.

Roof vents are usually priced between $297 and $583. Don’t forget to factor in installation labor costs of $40 to $77 per hour. How much a roof vent costs you depends on several factors, such as:

  • Type of roof vent
  • Roof slope
  • Size of the roof
  • Roof design
  • Architectural style
  • Climate

Here is a chart of different kinds of roof vents and their prices:

Type of Roof VentTypical Price Range (including labor)
Box$53 – $197
Turbine$58 – $250
Dormer$73 – $283
Power$233 – $1,100
Cupola$163 – $837
Gable$85 – $265
Ridge$297 – $583
Solar$318 – $1,200
Soffit$297 – $413

FAQ About Roof Ventilation Problems

Should I Replace or Repair My Roof Vent?

Whether or not you should replace your roof vent depends on the condition of your roof vent. If your roof vent is generally in good condition except for a damaged component, then repairs should suffice to resolve the problem.
However, it’s better to replace your roof vent if it shows these signs:

– Makes strange sounds
– Looks worn
– Broken or bent
– Holes or cracks
– Missing components

Roof vents have a lifespan of about 10 to 20 years. So, if your roof vent is nearing the end of its lifespan, it’s probably time to replace it. Or if you are replacing your roof, it might be a good idea to replace your roof vents as well.

Do Flat Roofs Need Ventilation?

Just like any other kind of roof, flat roofs also require ventilation. Like with a pitched roof, a flat roof without a good ventilation system suffers from stale, hot air or too much moisture buildup inside.

However, hot flat roofs, a type of flat roof with insulation placed on top of the roof decking, don’t need roof ventilation.

Is It Possible To Have Too Much Ventilation?

When it comes to attic ventilation, one should be like Goldilocks and find a balance of ventilation that is just right. If your home is over-ventilated, it can make your attic space chilly and drafty. Over-ventilated attics do not combat moisture buildup, so they are prone to water damage.

An over-ventilated attic can disrupt the natural airflow in the room and cause the same problems as a poorly-ventilated attic, including:

– Increased energy bill costs
– Moisture buildup
– Bad airflow
– Ceiling or roof is sagging
Mold growth
– Spongy roof
– Frost

Need to Vent Your Roof Problems?

Roof vents aren’t something you usually think about much. Although they may not seem important, good roofing ventilation protects your home from many issues. Without good ventilation, it could cause your roof serious problems, like extensive roof damage.

If you’re tired of dealing with common roof ventilation problems, hire a roofing professional to handle it for you. RoofGnome can help you find a roofing company near you today.

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Danielle Gorski

Danielle Gorski lives with her family in Texas. She has a degree in Professional Studies and a minor in marketing. Her hobbies include reading, drawing, and writing.