Attic ventilation is a critical component of all houses whether you live in a very cold climate like we have in Canada or whether you live in a very hot climate like Texas or Florida. Most people don't think about this at all until their home encounters problems. If air is not flowing through your attic, you are creating a world of serious problems for your house. These problems include but are not limited to:
1. Serious Ice Dams in Winter time.
2. Severely decreasing the life of your roof shingles or roofing system (yes, and even your "lifetime steel roof") because of excessive heat trapped in your attic.
3. Trapped moisture in the attic which can lead to the roof deck (plywood sheathing) rotting or turning black with mold.
4. Damage to insulation because of trapped moisture.
Any one of the above problems can lead to tens of thousands in damage!
Lack of ventilation is a problem our company encounters numerous times every year. Sometimes the fault is a severe lack of insulation. Other times it is a home owner or some company that got overly aggressive with attic insulation and insulated right out into the soffit area of the house. The worst house we ever encountered for attic ventilation was this one. We knew the attic was not breathing but we did not know how bad it was until we took the fascia board off.
The house above was literally suffocating! As you can see from the pictures, the homeowner had insulation blown in and they blew it straight into the soffit area and completely plugged it. This homeowner's attic was so hot we could not stay in it for long. She also had blackened roof decking from excessive moisture and her 10 year old shingles were already starting to crack and fatigue.
Atic ventilation is a very very simple concept! It relies on a common principle we all learned in High School Chemistry Class: hot air rises and cold air falls. Air expands when it gets hot and its molecules grow in size. Because of this, there are now fewer air molecules occupying the same amount of space and the hot air rises to the top. This is the reason hot air balloons float into the sky when the air is heated. It's also the reason attic ventilation works as it does.
Let's see how lack of attic ventilation vs. a well vented attic operates in two seasons:
The left side of this picture shows an attic that is not ventilated and can not breathe. The attic temperature is astronomical. The roof shingles are getting cooked and the A/C runs excessively. The right side shows an attic almost as warm as the outside temperature. The outside air enters in through the soffit area of the home and exits out of the roof vents keeping the attic cool and the house breathing.
In my professional opinion, the damage to an unvented attic in winter is greater than in summer. Here you see moist warm air trapped in the attic and this is why Ice Dams form. In an unvented attic in winter the insulation gets wet causing mold and mildew issues. The snow on the roof deck melts prematurely causing ice dams to form at the roof edge which can lead to water backing up into the house. A properly vented attic keeps the moist hot air flowing out of the attic mitigating these potential problems.
It's really this simple. You must have ample soffit and attic venting with a clear unclogged path from the soffit into the attic so the air can flow. If your attic isn't breathing, your house is in serious trouble.
If you are unsure about your attic ventilation, leave it to the professionals. You can contact us at www.theeavestroughcompany.com or call us at 905-966-2564. We would be happy to help.
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