How Roof Life Is Being Reduced Due To IMproper Attic Ventalation
Are you preparing to have your roof replaced? A very critical aspect of roof replacement is making sure the attic is vented properly. Over the years we have seen really good roofers make the huge mistake of replacing roofs with perfect technical installation skills but fail to properly address attic ventilation calculations. You will see in the diagrams below why proper attic ventilation is so important.
Diagram 1: Heat Issues Due To Improper Venting
As you can see in diagram 1 when an attic is not properly vented the hot air from your home gets stuck in the attic. The heat trapped in the attic in turn over heats your home. Not only does this "cook" the roof and reduce the life of the shingles and roofing system drastically, it also causes your energy bill to skyrocket due to the cost of running the air conditioner more to keep the temperature down.
Diagram 2: Moisture In The Attic
In diagram 2 you will see possibly the most destructive side effect of improper venting. Everyday household activities such as showering, cooking and heating the house releases heat and moisture into the attic. Its very common to see an attic that is not properly vented take on moisture and begin to condensate. Condensation can be the worst nightmare of a building structure. The damp atmosphere and water damages wood and other properties compromising the framing, insulation and other items.
Proper Venting
To avoid the issues shown above make sure you or your contractor addresses the ventilation of your home. They should get into your attic to make sure your insulation is not blocking the eave/soffit vents. You should also make sure your exhaust, which is typically AF-50 vents or ridge vents meet recommended calculations. Here is a simple and common attic vent calculation (please check local codes which always supersede principals):
From the GAF website:
Use this calculator to help determine the proper amount of attic ventilation based on U.S. FHA 1/300 guidelines.
Use this calculator to help determine the proper amount of attic ventilation based on U.S. FHA 1/300 guidelines.
- Proper attic ventilation consists of a balance between air intake (at your eaves, soffits or fascias) and air exhaust (at or near your roof ridge).
- The U.S. Federal Housing authority recommends a minimum of at least 1 square foot of attic ventilation (evenly split between intake and exhaust) for every 300 square feet of attic floor space.
- Always have a balanced ventilation system. In no case should the amount of exhaust ventilation exceed the amount of intake ventilation.
Visit The GAF Attic Calculator On The Link Below
For A Complete Study Course & Test On Attic Calculation Download Airvent II's Principals of Attic Ventalation Manual.
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Different Types of Attic Intake & Exhaust
Thank you for reading our Reliable Contractors Network blog! Do you have some critical information to add to the post or a preferred method of venting? Please comment below.
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