Short-Circuit Ventilation System

Only The Strongest Survive

In the picture above the roof system is using a ridge vent and wind turbine for attic exhaust. Regardless of the amount of attic intake this roof is receiving, having two different attic exhaust products will cause this home and roof to experience heating and cooling problems. Unfortunately utilizing more than one type of attic exhaust product will cause one to act as intake and the other as exhaust, leaving large areas of the attic unventilated and increasing the potential for possible weather infiltration problems. The perception would be that the more exhaust you have the cooler your roof is going to be or the less moisture buildup your roof will experience. This simply isn’t the case and will cause exactly the opposite to happen to incorporate several different types of exhaust or intake.

Having a short-circuited roof ventilation system is commonly found in homes where the consumer is misinformed about the impact of their roof ventilation decisions. The worst thing you can do is start adding additional can vents or wind turbines because your home feels like it’s on fire during the summer. Incorrect roof ventilation can and will destroy your roof. Don’t make the same mistake as the homeowner above did, be informed and be proactive.

Why Roof Ventilation Matters

Lets cut to the chase. We discuss, educate and write about roof ventilation in abundance because nine out of ten roofs age prematurely due to poor roof ventilation. There are several reasons why your roof may need to be replaced or require substantial roof maintenance, but your ventilation system can be your greatest asset in cutting energy costs and improving the durability of your roof.

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What Are Your Options?

Having a balanced roof ventilation system can be accomplished several different ways, but not all of the options are created equally. Here is a list comprised of the different products that may be used for attic exhaust and intake to help you obtain a balanced roof ventilation system.

Attic Exhaust

Whether you have an existing roof, or you’re participating in new home construction, can make a difference in which options you have available for attic exhaust. Nearly all new homes should be constructed with a ridge vent, although very few are, because of the ease for installation and ventilation benefits. Existing roofs may not always be able to install a ridge vent or it may not be the most cost effective solution. When in doubt, obtaining the advice of a roofing professional is recommended. See our list below for the pros and cons of the different types of attic exhaust products you can choose to use:

5 Turbines = 15 Roof Louvers = 42 Feet of Ridge Vent

Attic Intake

Our list of attic intake products doesn’t have a good, better, best system to help determine the best solution for ventilating your roof. Instead, the ideal system should allow continuous uniform airflow across the entire roof surface. However, bird blocks are the least effective, and most commonly found option for attic intake, because they are the most restrictive system for allowing airflow through. All of the other intake systems provide a continuous airflow system across the entire face of the product. It’s important to note that air follows the path of least resistance and should enter the attic at the lowest point to provide the most effective ventilation system possible. Therefore using an exhaust vents for intake is not recommended.

Completing The Ventilation System

In the end, it doesn’t matter what combination of exhaust and intake products you use so long as the intake area is equal to or exceeds the exhaust area. According to building codes, a balanced ventilation system means at least 50% of the required vent area must be intake and 50% exhaust. One type of exhaust and intake product should be selected and used rather than multiple types. When you have several types of products in use, the stronger product will pull from the other one creating a potential short-circuit in the ventilation system. These are found commonly in new construction developments as a result of cost cuts or lack of roofing knowledge.

Having the knowledge and understanding about roof ventilation will help you make an informed decision about the options you have for improving your home’s heating and cooling. There are quite a few different factors and numbers that come into play that will help you make your decision. Instead of boring you with all the details Roof Life of Oregon can provide you with your best solution through a free roof maintenance inspection. For more information on ways to improve your roof ventilation, and ways you could hinder it, please visit our roof ventilation section on our blog.

During an inspection of a Beaverton Condominium complex, we noticed the use of can vents placed low on the roof for intake instead of having intake cuts below the roof line.

The question is, does this roof ventilation system actually work? Yes, however it’s not the proper use of can vents. Can vents are designed for the outtake portion of your roof ventilation system. It would be like using a fork to flip burgers on the grill instead of burger spatula; it works, but it’s not the most efficient use of your cooking toolbox.

What we would do is either put in a soffit vent or what we call a SMART vent. A soffit vent allows outside air to enter the attic at the lowest point of the roof—along the underside of the eave. They’re most effective when used in conjunction with a continuous ridge vent. A SMART vent is, a tapered, under shingle plastic product designed for installation along the soffit edge of the roof or the facing edge of dormer rakes and goes virtually unnoticed. It allows air to flow freely through the 1″ roof decking slit providing more than adequate soffit ventilation to maximize ridge vent effectiveness. (source http://www.dciproducts.com/html/smartvent.htm)

For more information about having an energy efficient roof please visit our RL Green Contractor page.

Having a properly ventilated roof contributes more to your family than having an energy efficient home. Having a properly ventilated roof contributes more to your family’s budget than keeping your heating and cooling costs down. Having a properly ventilated roof means your family’s head, respiratory system, and ultimately health is protected from mother nature and all of her lack luster qualities. Mold and fungus can find their way into your roof and attic making asthma five times more likely to strike one of your loved ones when compared to a family with a properly ventilated roof.

Doesn’t it make sense to protected your loved ones from asthma? All it takes is one free roof maintenance inspection by Roof Life of Oregon to create peace of mind that your roof is protecting your family for the duration of your roof’s life.

If we didn’t tell you that this type of shingle has a natural lifting and checkerboard look, then the picture below would be a dead giveaway that this roof has a roof ventilation issue. We’ve discussed in a previous post about the issue of roof ventilation overload and the roof image displayed below is another great example of poor roof ventilation layout. This roof is using both a ridge vent and a power fan for roof ventilation. The combination of a ridge vent and a power fan will cause an undesirable effect on your roof ventilation system, circumventing the desired result.

If your roof looks like this, and you didn’t pay for the curling style, than your roof is giving you a hint that it’s time for your roof to be inspected. Roof Life of Oregon provides free estimates to help ensure your roof looks good, works right, and lasts longer. Give us a call at (503) 925-0125 or fill out one of our online roof estimate forms.

Installing a power fan is a great way to add the necessary roof ventilation you need. However, the power fan needs to be installed properly and the photo below is a great example of an incorrect power fan installation.

At Roof Life of Oregon, we believe that everything should be used in moderation. Having more can vents than required is a great way to void the warranty on your roof. Using enough mastic on your power vent to seal the Leaning Tower of Pisa to the floor can also cause you some major problems. Especially when your power fan is incorrectly installed and must be removed.

Another problem with installation of this power fan is it was simply placed over the whole of a previous can vent (This can be seen via the photo below). This power fan should have been cut into the roof instead of placing it directly over the top of the whole. In fact, we’re not even sure if there is a whole cut underneath the power fan to pull air through the roof.

Since 1983 Roof Life of Oregon has provided the Greater Portland area with an expertise and workmanship incomparable to other roofing contractors. If you’re interested in improving your roof’s ventilation system please call 503-925-0125 or fill out one of our free estimate forms. We’ll work with you to ensure your roof works right, lasts long, and looks great.

This roof has enough can vents to exhaust the entire roof clustered together on one side of the house instead of distributed evenly. Additionally, eight of the eleven visible can vents are obsolete because they are placed directly next to each other. The cluster of six can vents, located on the bottom left side of the photo, are circulating air from each other horizontally and then are restricting air from circulating vertically through the entire roof. Ideally, can vents should be placed at the highest point possible to allow the air to flow in from vents located underneath the gutters, through the roof and out the can vents. Not allowing air to flow through the entire roof, or limiting air exhaust to a limited section, will cause your roof to overheat and degredate at least two times faster than normal. Poor roof ventilation causes 9 out of 10 roofs to prematurely fail.

We take roof ventilation very seriously and we’re proud to say we’re one of the few green roofing contractors in the state of Oregon. If your attic has been obscenely hot this summer, chances are you might have a roof ventilation issue. Give us a call at (503) 925-0125 or request a roof inspection and our roof consultants will give you a full assessment including your roof ventilation.

To the untrained eye, this roof appears to only have a power fan for roof ventilation, but if you look really closely you can see the ridge line looks different. This ridge is actually using what we call a ridge vent. A ridge vent is commonly used in place of can vents, providing roof exhaust, and the same amount of ventilation without the big black squares all over your roof. Many homeowners desire a ridge vent because they believe that it blends into the roof line and provides a more attractive home.

The problem with having a ridge vent AND a power fan is the roof has now circumvented the desired ventilation result. In the case of roof ventilation, more is not necessarily better. What we would prescribe in this particular case, is to choose one or the other: the ridge vent or the power fan. Having both systems in place is causing the air to move rapidly at the top of the roof and more slowly at the bottom. In fact, the power fan is pulling air from the ridge vent not uniformly through the entire roof.

If your home has been obscenely hot this summer you may have a roof ventilation problem. Roof Life of Oregon has trained its roof consultants on the most effective roof ventilation techniques that will allow for proper heating and cooling and save you thousands in energy costs. Call (503) 925-0125 or request a free roof inspection to ensure your roof isn’t prematurely failing because of your roof ventilation.

Daniel White answers that question for us in the following video clip.

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SCRIPT

We’re out in Newberg today and we have an interesting ventilation issue going on that I’m not sure that the homeowner Is aware of, so I’m going to talk to them about it shortly. Do you notice these vents? You can see the vents up at the ridge line here. You notice that there are some vents here. The problem is these vents should not be on this home. The very end of this house, underneath this gutter, there are vents that actually allow the intake. What happens is air is supposed to pull from the very bottom, goes all the way up inside the attic, runs all the way to the top vent. Not this one, all the way to the top vent. What’s happening is the system is being short circuited. It’s pulling the cool air from here, drawing it up into the attic, and it’s exhausting here. It’s not pulling and going up to this one here, so this whole upper section is not venting the way it’s supposed to. I want you to look at the shingles as I come up here at this weird angle. You can see right above the roof, those vents, you can see that this line all right above those vents is starting to curl, it’s starting to buckle, it’s having an issue. It’s doing it on this other side also. Right above those vents, we’ll get down close so you can see it, they’re beginning to curl. You can see them actually start to lift up and begin to curl and it’s right above the vents on both sides. Again, that’s because of these intake vents. They’re not acting as an intake; they’re acting as an exhaust. It’s pulling from down there, going all the way up, exhausting here, this area right here, it’s just dead air, it’s not doing what it’s supposed to do.

Our roof maintenance consultants are trained and experienced at calculating the exact number of can vents required to make sure your roof works right and lasts longer.

The National Roofing Contractors Association (NRCA) stated in 2007 that the number one cause for premature roof failure in the US is due to improper roof ventilation. Why is this happening? Perhaps one reason is that most low cost, high volume, roofers use roofing crews that get paid by the footage. Speed is the key! A supervisor stretched thin can only catch so much. The roofing contractor working on small margins will let things slide. A homeowner getting 15 years out of his 40 year roof takes a distant second to his immediate needs. Spending 30-40% more in energy to cool and heat your home doesn’t even concern this roofing contractor. Sounds like a real self-centered jerk, doesn’t he?

The type of damage your roof structure and roofing material will experience is the roof granular falling off into the gutters, spider cracks in the fiberglass mat, the underlayment plywood will bow and delaminate, and poisonous molds, mildew, and fungus can grow in your attic space. If a under ventilated roof is left to run its barrage of problems the homeowner will have to replace the plywood, spray the attic space for mold and mildew damage, cut in the right amount of roof ventilation, and then re-roof it again. The roof shingle manufacturer wont help you with the costs of your replacement because their warranty was voided when the roof contractor under ventilated the roof!

As one of Portland’s premier roofing contractors the first thing that Roof Life of Oregon does when called to your home for a roof replacement proposal is we check the attic. Correct roof ventilation is a top priority to getting the full service life out of a roof system. Both intake as well as exiting air is important. For every 200 square feet of attic space a roof needs 64 cubic inches of intake/exhaust. This will keep the roofing as cool as possible and create a barrier of active air that will save you 1000’s of dollars. We don’t stop there either; we continue roofing your home by installing complementary roof components that will last you a lifetime. A roof engineered to last a lifetime. That’s why Roof Life of Oregon has Portland’s only transferable lifetime workmanship warranty.