Proper Attic Ventilation for Your New Roof:
Attic ventilation plays a critical role in the health of your new roof system. A poorly ventilated attic can not only shorten the lifespan of your new roof, but also damage wood sheathing or decking due to excessive heat and/or moisture. Not only can an inadequately ventilated attic damage your roof, it could also create an unhealthy environment in your home if moisture build up leads to mold growth in your attic. Here are some things to consider when choosing the best way to ventilate your new roof system.
Attic Ventilation Types
Here are a few of your best options when choosing attic ventilation for your new roof:
While discussing ventilation, exhaust is typically the first thing that comes to mind. However, intake ventilation is just as important, and is commonly overlooked. Most often, intake ventilation is achieved by utilizing the soffit area along the eaves of the home since this is the lowest area of the roof, and the safest air entry point (the top of the roof is used for exhaust). We recommend that you inspect the soffit area of your home first to see if it currently ventilates. Look for holes or slots on the exterior where air could breathe into the home. If holes or slots are present along the soffit area of your home, then there is a good chance your home has the proper intake ventilation necessary for a healthy roof system. Although this does not completely ensure that the intake ventilation is okay, for example sometimes vented vinyl or aluminum soffits are installed to cover a solid wood soffit to reduce the maintenance needed to paint the wood materials every few years. In other blocked venting situations, the home’s attic insulation blocks the passage of air into the attic. A remedy for this problem would be to install styro-foam baffles that hold back the insulation, and also provide a clear passage for air to enter the attic space. This would be a good weekend project for a DIY type of homeowner who is not afraid to navigate the attic safely. If your attic does not currently have intake ventilation, here are some common products used for intake ventilation:
Soffit Vents – This is one of the most safe and effective ways to move air into the attic. The soffit area is protected under the roof from the weather, and is at the lowest possible point vertically in the roof’s construction. Both aluminum and vinyl soffit materials have either holes or slots, and are available in a variety widths and colors depending upon aesthetics. Aluminum is good for larger over-hangs since the aluminum is sturdier to maintain a flat soffit appearance. If the soffit area is not too deep, and the home is frequently power washed, then perhaps vinyl might be the right option for you since the paint can be removed from the aluminum soffits under high pressure washing. Products like Certainteed’s Invisivent are designed in a clever way to conceal the venting holes in vinyl soffit materials (if you do not want to see the holes or slots). Even vinyl porch ceiling products have been designed for attic ventilation like Mastic Exteriors Pro-Bead Classic Beaded soffit by PlyGem. James Hardie vented soffit may be a great alternative if you have a cement-board siding product on your home. Just keep in mind that in most situations, the gutters and fascia may need to be affected or manipulated to correct the intake ventilation problem with soffit vents.
Roof-top Intake Vents – Not quite as safe as soffit vents, but more leak-proof than vented drip edge, roof-top intake vents are a great solution when soffit vents aren’t existing, or if there is no soffit overhang due to the construction design of the structure. Owens Corning’s VentSure InFlow vent is a perfect example of a roof-top intake for those hard to vent situations, and most shingle manufacturer’s offer a similarly designed product to complement their roof systems too.
Now that we understand intake ventilation, let’s discuss exhaust ventilation. By far, ridge-vents and fans are the most popular and commonly recommended ways to achieve attic exhaust. Cupolas, gable vents, and turbines are no longer considered effective ways to exhaust an attic space. Here is some information to think about when choosing the right exhaust system for your new roof.
Ridge-Vent – Ridge-vents are the most preferred way to exhaust an attic space. The old aluminum ridge-vents, popularized in the 1980’s, were prone to leaking and did not vent as well as the modern versions of ridge-vents used today. They were typically fastened with nails that were sealed with caulk. When the caulk failed, the nails leaked, and the ridge-vent could eventually blow-off the roof. Now that we understand the failures of the old aluminum ridge-vent systems, manufacturers have worked to redesign more leak-proof systems, and steer away from exposed fastener aluminum ridge-vents. Rolled ridge-vents like GAF Cobra receive a shingle cap attached above the product to protect the fasteners from needing re-sealed like the old aluminum ridge-vents. These rolled ridge-vent systems are not perfect though, and can leak as the shingle caps above begin to weaken and fail. An even better design are the baffled ridge-vents like TAMKO’s CoolRidge or Certainteed’s RidgeVent. These baffled ridge-vents are also topped with a shingle cap similar to rolled ridge-vent, but are made of a durable plastic that will not allow water to leach through even if the shingle cap fails. Not only that, but they breathe much more freely than any other ridge-vent, and can be purchased with or with-out filters to keep insects out. Ridge-vents utilize a 2”-3” opening along the ridge of the roof to breathe properly. So be sure to check the attic’s construction to make sure that a ridge pole or some other obstruction can inhibit the ridge-vents ability to function. In these situations, one might install consecutive box vents just below one side of the ridge to achieve natural aspiration. Just keep in mind that each box vent penetration is an opportunity for a roof leak later on.
Attic Fans – In situations where the ridge length is very short, or where a ridge obstruction makes ridge-vent non-operational, then perhaps an attic fan is the right solution for your new roof system. Power attic fans like those manufactured by AirVent, are controlled with a thermostat, humidistat, or both, and are available in many sizes depending upon the size of your attic space. When installing these fans for ventilation, be sure to hire an electrician to wire the fan(s) to either an existing power supply wire in the attic, or they will need to run an entirely new power supply wire into the attic. If no power supply is present, then a solar fan from SolaTube may be an alternative option. Sun exposure to the home must be a consideration with a solar product like this. These solar fans are not nearly as powerful as the electric fans, but do provide consistent air movement all day while the sun is up, as opposed to the power fans that only run in short bursts as needed. Unlike ridge-vent and other natural aspirated venting systems, fans have motors that can fail, and should be checked frequently to ensure that the fan is operational to avoid any damage that can compromise your new roof system.
If conditions allow for it, a ridge-vent in combination with soffit vents is the preferred way to vent the attic. An alternative ventilation combination may be a better way to approach specific situations depending upon the home’s construction or design. Online tools like an attic ventilation calculator can be helpful with understanding ventilation based on the size and shape of your attic. Nothing beats finding a great roofing contractor like Roof Right Inc. in Maryland. Companies like Roof Right perform a thorough rooftop inspection, attic inspection, and provide guidance on how to best suit your situation.
Pick Roof Right!
Roof Right, located in Carroll County, Maryland, works directly with clients to ensure that every step of the process is as straightforward and stress-free as possible. Since 1994, we have been providing excellent service to Anne Arundel County, Baltimore City, Carroll County, Harford County, Howard County and Montgomery County. Schedule a virtual estimate today!