If you're a homeowner, a basic knowledge of your roofing system and all the sub-systems that work with it is a necessity. Knowing how your gutters, downspouts, roof vents, and attic insulation work together can help you keep your roof and your house healthy with greater success. Here are four reasons why responsible homeowners keep their roofs ventilated.
1. Reduces Heat-Related Shingle Damage
The sun can damage your asphalt shingles in several ways. The first is UV damage, which ventilation doesn't help with, but ventilation can help prevent or reduce thermal shock and shingle overheating.
Thermal shock occurs when your shingles have to expand and contract a great deal each day because the temperature varies so widely. This stretches their elasticity to the limit until they start to fail, allowing damage such as buckling and creasing.
2. Prevents Mold and Rot
Although rain probably springs to mind first when you think of water damage, you need to be aware that indoor humidity can also cause problems when not vented properly. That's because the warmest, most humid air in your house rises up to the roof, where the water condenses onto the underside of the sheathing.
This isn't just a problem in humid climates. The activities you do in your home, such as cooking, bathing, showering, and breathing, release huge amounts of moisture into your home's air. However, if you do live in a climate that's humid, the air already has a lot of water in it to begin with, which can make the problem even worse.
Once the water has condensed on the roof deck, the water starts to soak in and get the sheathing all wet. The sheathing can then start to delaminate (fall apart) and can get moldy as well. The water drops can also drip down to the insulation and cause water damage and mold and may even soak through the insulation and make watermarks on your ceiling.
Proper ventilation systems should vent the wet air before it can leave water droplets on the roof deck.
3. Reduces Energy Needed for Cooling
Not only does good ventilation remove the wet air, it removes the hottest air. That's because hot air rises to the ridge of the roof, where outlet vents are located, allowing the hot air to escape. In the absence of a functioning ventilation system, the heat just builds up under the roof, increasing the amount of heat that transfers through the attic floor into your house.
The attic insulation should reduce this heat transfer, but still, the more heat is available in the attic, the more will get through to your home. Additionally, since ventilation problems can cause condensation problems, your insulation might be wet, and wet insulation transfers heat rather than guarding against it.
A good ventilation system that keeps your attic insulation dry and helps hot air to escape through your ridge vents can reduce the unwanted heat gain to your house in the summer. This, in turn, helps to lighten the load on your AC system, meaning you don't have to pay as much in energy bills during the summer.
4. Discourages Moisture-Loving Pests
Poor ventilation can make your roof and attic more vulnerable to pests. Firstly, the increased moisture in your roof deck and other wood components make them a target for termites that love damp wood. Secondly, the water damage lets raccoons and other critters in easier to chew and claw their way into the attic.
Adding vents to keep pests out may seem counterintuitive since vents can become access points for pests too. To prevent this, cover your vents with strong wire mesh, using the type with holes small enough to exclude termites. If you're not sure what gauge to use, talk to your roofing contractor.
These four reasons demonstrate why keeping your roof well-ventilated is so critical not only to roof health but to your home's comfort levels, energy use, and pest protection. For more information about roof ventilation systems, help with a condensation problem, or any other roofing issues, contact C & W Roofing, Siding & Window Co. today.